Stian Svelle

• Njoroge, Peter Ng'ang'a; Solemsli, Bjørn Gading; Wijerathne, Asanka; Berdiell, Izar Capel; Seremak, Agnieszka Patrycja & Chiesa, Mario [Vis alle 16 forfattere av denne artikkelen] (2025). Influence of Aluminum Distribution in Cu-MOR Systems on Methane-to-Methanol Conversion: A Combined Experimental and Theoretical Study. Journal of Physical Chemistry C. ISSN 1932-7447. 129(44), s. 20044–20056. doi: 10.1021/acs.jpcc.5c06045. Fulltekst i vitenarkiv Vis sammendrag

  A series of copper-mordenite (MOR) samples of different provenances were investigated in the methane-to-methanol (MTM) reaction after preparing their copper-exchanged analogues. Noticeable activity improvements were observed when biasing the Al framework distribution of the confined side-pocket toward 12-ring openings (T2 and T4 enrichment) over 8-ring openings (T1 and T3), achieved by using K+ or Na+ in the synthesis gel, respectively. This was rationalized by performing a geometry optimization algorithm using density functional theory (DFT) simulations, which revealed distortions in the structure of the pores among different idealized zeolite models. From this, effects on the copper species were observed, as evidenced from both electron paramagnetic resonance (EPR) spectroscopy and operando X-ray absorption spectroscopy (XAS), which suggested varying monomeric [Cu]2+/[CuOH]+ concentrations with intrinsic copper reducibility differences. Monte Carlo simulations on selected MOR structures of the experimental series exposed dimeric structures with more acute Cu–O–Cu angles, thereby suggesting a more reactive system for Cu-MOR based on K+ in the synthesis gel, in line with the experimental finding. The combined insights from simulations, calculations, and experiments have enabled us to establish a synthesis-structure–activity relationship for mordenite in methane conversion, highlighting the reactive interplay between pore geometry and copper speciation.

• Berdiell, Izar Capel; Cordero-Lanzac, Tomás; Junge, Nicolai Haaber; Nogueira, Liebert Parreiras; Vaughan, Gavin & Michiel, Marco Di [Vis alle 10 forfattere av denne artikkelen] (2025). X-ray absorption and diffraction computed tomography characterization of deactivation and coking in spray-dried ZSM-5/alumina catalysts. Catalysis Science & Technology. ISSN 2044-4753. doi: 10.1039/d5cy01023c. Fulltekst i vitenarkiv Vis sammendrag

  One of the main drawbacks of acid-based heterogeneous catalytic processes involving hydrocarbons is coke formation. Still, research on shaped catalysts remains limited. The main objective of this study was to gain insight into the catalyst deactivation in the methanol-to-hydrocarbon (MTH) reaction. Diffraction and absorption computed tomography experiments were performed on spray dried, hollow semi-spherically shaped ZSM-5/alumina catalysts of approximately 250 microns in size. The catalysts were employed in the MTH reaction at two different pressures, resulting in varying degrees of coking. Absorption tomography (0.027 μm3 per voxel) revealed the structural features and sponginess of the shaped catalysts. These are not perfect spheres; they rather have openings as they burst during the spray drying process. Further, high resolution powder X-ray diffraction computed tomography slices (0.125 μm3 per voxel) were analyzed by parametric Rietveld refinement. The analysis showed that the catalyst and binder overall are rather homogeneously spatially distributed within each sphere, but bubbles and agglomerates of a single phase are frequent. In addition, it is demonstrated that there were no coking gradients across the sphere wall at both partial and full deactivation. This indicates that the binder and the catalyst shape and size were suitable for the reaction conditions. Indeed, the catalyst lifetime was almost doubled relative to the pure, powdered zeolite catalyst. A series of catalysts with varying degrees of deactivation have been fully characterized ex situ, suggesting significant spillover of coke from the zeolite to the alumina matrix. These findings demonstrate the need for greater efforts to understand the formulation of shaped catalyst objects, where the matrix should not only hold the components together but also support and enhance the overall catalytic process.

• Seremak, Agnieszka; Goeminne, Ruben; Berdiell, Izar Capel; Lundegaard, Lars F.; Speybroeck, Veronique Van & Svelle, Stian (2025). Exploring the guest–host relationship for zeolite Y: a synergistic structural and theoretical investigation. Journal of Materials Chemistry A. ISSN 2050-7488. 13, s. 35755–35755. doi: 10.1039/d5ta04948b. Fulltekst i vitenarkiv Vis sammendrag

  Understanding the mobility and distribution of cations in the presence of additional guest species within the zeolite framework is inherently very complex because several thermal and chemical processes occur simultaneously. In this study, the dehydration of zeolite Na-Y was studied using in situ powder X-ray diffraction (XRD). The crystal structure parameters, both the evolution of lattice parameters and the occupancies of sodium at specific positions in the model, were monitored upon heating. A complementary computational study was performed to understand interactions between the framework, cations, and water at the molecular level. Grand Canonical Monte Carlo (GCMC) simulations provided initial insights into water adsorption. Machine Learning Potentials (MLPs) were then trained to the ab initio Potential Energy Surface (PES) using a deep neural network, modeling the dynamics of the framework and cations at various water loadings. Strong agreement between computational results and experimental data reveal that upon dehydration, zeolite Na-Y initially contracts due to water removal, but subsequently expands as sodium cations migrate to the double 6-membered rings (site I). This study demonstrates significant benefits of integrating parametric Rietveld refinement and Machine Learning assisted Molecular Dynamics simulations in understanding dynamic behavior of guest molecules in nanoporous materials at operating conditions and interpreting complex and convoluted experimental data.

• Seremak, Agnieszka Patrycja; Berdiell, Izar Capel; Arstad, Bjørnar; Fjermestad, Torstein & Svelle, Stian (2025). Investigating the Flexibility of H-ZSM-5 Zeolite Upon Adsorption of Coke Precursors: A Theoretical and Experimental Approach. Journal of Physical Chemistry C. ISSN 1932-7447. 129(2), s. 1183–1197. doi: 10.1021/acs.jpcc.4c07349. Fulltekst i vitenarkiv Vis sammendrag

  The flexibility of the H-ZSM-5 zeolite upon adsorption of selected coke precursors was investigated using both theoretical and experimental approaches. Four structural models with varying active site locations were analyzed through density functional theory (DFT) simulations to determine their responses to different types and quantities of aromatic molecules. Complementary experimental analysis was performed, allowing for a direct comparison with the theoretical findings, using thermogravimetric analysis (TGA), nitrogen adsorption (N2 adsorption), solid-state NMR, and X-ray diffraction (XRD). By employing proposed flexibility descriptors, significant structural changes in the MFI-type zeolite framework were identified, particularly in the unit cell parameters and the morphology of the straight channels. These changes were driven by electrostatic repulsion between adsorbates and by electrostatic attraction between adsorbates and the zeolite framework. The observed structural changes depended on both the active site location and the size and number of coke precursors. Consistent trends in structural flexibility were observed in both experimental and theoretical studies, primarily driven by variations in organic species loading. Our findings show the critical importance of active site location in influencing the magnitude of framework flexibility, which, in turn, affects the stabilization and accommodation of different coke precursors within the zeolite structure.

• Berdiell, Izar Capel; Lundegaard, Lars F.; Beato, Pablo; Michiel, Marco Di; Wragg, David Stephen & Svelle, Stian (2025). Spatiotemporal investigation of the regeneration of a shaped zeolite catalyst extrudate using operando powder X-ray diffraction computed tomography. Journal of Catalysis. ISSN 0021-9517. 450. doi: 10.1016/j.jcat.2025.116300. Fulltekst i vitenarkiv Vis sammendrag

  We have used operando powder X-ray diffraction computed tomography (PXRD-CT) analysed by parametric Rietveld refinements to monitor the regeneration of a deactivated ZSM-5 zeolite based extrudate employed as a catalyst in the methanol-to-hydrocarbon reaction. This investigation thus advances beyond previous studies of pure, powdered zeolites. We follow the coke oxidation by monitoring three XRD based descriptors. Lattice relaxation, monitored as the difference in length of the a- and b-lattice parameters (a-b), occurs first at the core of the extrudate and progresses towards the outer surface. This demonstrates a radial distribution of different coke species, wherein the heaviest, more oxidation resistant coke is matured near the external surface of the extrudate. In contrast, the total non-framework species mass (NFSM) decreased more uniformly throughout the extrudate, suggesting that chemical transformations of the coke species can occur prior to full oxidation. This notion is supported by in situ temperature programmed oxidation, which demonstrates that the regeneration of the ZSM-5/binder composite occurs in two distinct steps. We also observe that irreversible (hydro)thermal damage occurs in the severely coked regions of the extrudate during regeneration. Additionally, we demonstrate that the three different XRD based descriptors carry slightly different and complementary information. The (a-b) descriptor describes lattice distortion induced by rigid coke species. The total non-framework species mass (NFSM) and the unit cell volume (UCV), in contrast, capture all guest species, including volatile compounds and water. However, as a drawback, the UCV is strongly influenced also by thermal effects, whereas the (NFSM) is virtually unaffected by temperature.

• Solemsli, Bjørn Gading; Berdiell, Izar Capel; Prodinger, Sebastian; Kvande, Karoline; Deplano, Gabriele & Olsbye, Unni [Vis alle 9 forfattere av denne artikkelen] (2024). Reactivity of methoxy species towards methylation and oligomerization in Cu-zeolite systems. Catalysis Today. ISSN 0920-5861. 436. doi: 10.1016/j.cattod.2024.114729. Fulltekst i vitenarkiv Vis sammendrag

  Ethylene, propylene, and benzene were investigated as molecules for extracting methoxy intermediate species formed during the cyclic partial oxidation of methane in Cu-exchanged zeolites, promising materials for the step-wise methane-to-methanol (MTM) reaction. 13C-labeled reaction studies reveal that alkenes preferentially undergo oligomerization followed by cracking, while benzene is successfully methylated, forming toluene. Benzene methylation further showcases the methyl species to behave similar to surface methoxy species formed on Brønsted acid sites in methanol-to-hydrocarbon (MTH) reaction. However, benzene is only able to extract a fraction of the methyl species compared to the methanol produced with water extraction, indicating either steric or intrinsic mechanistic effects to limit the full potential of the methyl pool inside the framework. We infer the presence of reactive methoxy species on Brønsted acid sites generated under reaction conditions, revealing their potential as a synthetic platform to form additional products from methane.

• Lanzac, Tomas Cordero; Berdiell, Izar Capel; Airi, Alessia; Chung, Sang-Ho; Mancuso, Jenna & Redekop, Evgeniy [Vis alle 16 forfattere av denne artikkelen] (2024). Transitioning from Methanol to Olefins (MTO) toward a Tandem CO2 Hydrogenation Process: On the Role and Fate of Heteroatoms (Mg, Si) in MAPO-18 Zeotypes. JACS Au. 4(2), s. 744–759. doi: 10.1021/jacsau.3c00768. Fulltekst i vitenarkiv Vis sammendrag

  The tandem CO2 hydrogenation to hydrocarbons over mixed metal oxide/zeolite catalysts (OXZEO) is an efficient way of producing value-added hydrocarbons (platform chemicals and fuels) directly from CO2 via methanol intermediate in a single reactor. In this contribution, two MAPO-18 zeotypes (M = Mg, Si) were tested and their performance was compared under methanol-to-olefins (MTO) conditions (350 °C, PCH3OH = 0.04 bar, 6.5 gCH3OH h–1 g–1), methanol/CO/H2 cofeed conditions (350 °C, PCH3OH/PCO/PH2 = 1:7.3:21.7 bar, 2.5 gCH3OH h–1 g–1), and tandem CO2 hydrogenation-to-olefin conditions (350 °C, PCO2/PH2 = 7.5:22.5 bar, 1.4–12.0 gMAPO-18 h molCO2–1). In the latter case, the zeotypes were mixed with a fixed amount of ZnO:ZrO2 catalyst, well-known for the conversion of CO2/H2 to methanol. Focus was set on the methanol conversion activity, product selectivity, and performance stability with time-on-stream. In situ and ex situ Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), solid-state nuclear magnetic resonance (NMR), sorption experiments, and ab initio molecular dynamics (AIMD) calculations were performed to correlate material performance with material characteristics. The catalytic tests demonstrated the better performance of MgAPO-18 versus SAPO-18 at MTO conditions, the much superior performance of MgAPO-18 under methanol/CO/H2 cofeeds, and yet the increasingly similar performance of the two materials under tandem conditions upon increasing the zeotype-to-oxide ratio in the tandem catalyst bed. In situ FT-IR measurements coupled with AIMD calculations revealed differences in the MTO initiation mechanism between the two materials. SAPO-18 promoted initial CO2 formation, indicative of a formaldehyde-based decarboxylation mechanism, while CO and ketene were the main constituents of the initiation pool in MgAPO-18, suggesting a decarbonylation mechanism. Under tandem CO2 hydrogenation conditions, the presence of high water concentrations and low methanol partial pressure in the reaction medium led to lower, and increasingly similar, methanol turnover frequencies for the zeotypes. Despite both MAPO-18 zeotypes showing signs of activity loss upon storage due to the interaction of the sites with ambient humidity, they presented a remarkable stability after reaching steady state under tandem reaction conditions and after steaming and regeneration cycles at high temperatures. Water adsorption experiments at room temperature confirmed this observation. The faster activity loss observed in the Mg version is assigned to its harder Mg2+-ion character and the higher concentration of CHA defects in the AEI structure, identified by solid-state NMR and XRD. The low stability of a MgAPO-34 zeotype (CHA structure) upon storage corroborated the relationship between CHA defects and instability.

• Lundegaard, Lars Fahl; Berdiell, Izar Capel; König, Nico; Junge, Nicolai Haaber; Beato, Pablo & Chernyshov, Dmitry [Vis alle 8 forfattere av denne artikkelen] (2023). Tracking deactivation of zeolite beta with and without a detailed structure model: XRD analysis and in situ studies. Microporous and Mesoporous Materials. ISSN 1387-1811. 366. doi: 10.1016/j.micromeso.2023.112911. Fulltekst i vitenarkiv
• Berdiell, Izar Capel; Braghin, Giorgio Bruno; Cordero-Lanzac, Tomas; Beato, Pablo; Lundegaard, Lars F. & Wragg, David Stephen [Vis alle 8 forfattere av denne artikkelen] (2023). Tracking Structural Deactivation of H-Ferrierite Zeolite Catalyst During MTH with XRD. Topics in catalysis. ISSN 1022-5528. 66, s. 1418–1426. doi: 10.1007/s11244-023-01780-0. Fulltekst i vitenarkiv Vis sammendrag

  Abstract We used the methanol-to-hydrocarbon (MTH) reaction as a shape-selective model reaction to investigate coke formation in zeolite H-Ferrierite. Despite being a 2D topology in terms of channel propagation, the FER framework displays a lattice expansion in all three dimensions of space upon deactivation. Therefore, the volume of the unit cell is an excellent X-Ray diffraction (XRD) descriptor for the catalyst deactivation. A model with dummy atoms added, also proved to be an accurate approach to measure the amount of internal coke and/or water inside the pore network correlated with thermogravimetric analysis results. While the catalyst deactivation of the H-Ferrerite during the MTH was fast, a comparably long induction period was observed. We were able to track such fast deactivation with the aforementioned descriptors by means of an operando XRD study by a standard laboratory diffractometer.

• Prodinger, Sebastian; Berdiell, Izar Capel; Cordero-Lanzac, Tomas; Bygdnes, Odd Reidar; Solemsli, Bjørn Gading & Kvande, Karoline [Vis alle 10 forfattere av denne artikkelen] (2023). Cation-induced speciation of port-size during mordenite zeolite synthesis. Journal of Materials Chemistry A. ISSN 2050-7488. 11(40), s. 21884–21894. doi: 10.1039/d3ta03444e. Fulltekst i vitenarkiv Vis sammendrag

  Mordenite (MOR) zeolite, an important industrial catalyst exists in two, isostructural variants defined by their port-size, small and large-port. Here we show for the first time how a systematic, single-parameter variation influences the synthesis out-come on the final MOR material leading to distinctly different catalysts. The cation identity has a direct impact on the synthesis mechanism with potassium cations generating the more constrained, small-port MOR variant compared to the large-port obtained with sodium cations. This was expressed by different degrees of accessibility ascertained with a combination of toluene breakthrough and temperature programmed desorption (TPD), propylamine TPD, as well as sterically sensitive isobutane conversion. Rietveld refinement of the X-ray diffractograms elucidated the preferential siting of the smaller sodium cations in the constricted 8-ring, from which differences in Al distribution follow. Note, there are no organic structure directing agents utilized in this synthesis pointing at the important role of inorganic structure directing agents (ISDA).

• Tezel, Elif; Sannes, Dag Kristian; Svelle, Stian; Szilagyi, Petra Agota & Olsbye, Unni (2023). Direct CO<inf>2</inf> to methanol reduction on Zr<inf>6</inf>-MOF based composite catalysts: a critical review. Materials Advances. doi: 10.1039/d3ma00345k. Fulltekst i vitenarkiv Vis sammendrag

  The pressing problem of climate change on account of anthropogenic greenhouse-gas emissions underlines the necessity for carbon capture and utilisation technologies. Several heterogeneous catalyst systems allowing the conversion of waste CO2 into desirable products, such as methanol, have emerged as promising and potentially viable solutions to this perennial problem. In particular, composite catalysts based on hexanuclear zirconium metal–organic framework matrices have shown much promise in the direct conversion of CO2 into value-added and useful products. Herein, we critically review the literature in this area and relate differences in composition, defect chemistry, and structural characteristics, their reaction conditions with their performance and stability in the thermocatalytic hydrogenation of CO2 to methanol, on the basis of both experimental and theoretical studies. We also highlight the obstacles in directly comparing the performance of these systems for CO2 hydrogenation and suggest potential solutions and opportunities for further advancement.

• Kvande, Karoline; Prodinger, Sebastian; Solemsli, Bjørn Gading; Bordiga, Silvia; Borfecchia, Elisa & Olsbye, Unni [Vis alle 8 forfattere av denne artikkelen] (2023). Cu-loaded zeolites enable the selective activation of ethane to ethylene at low temperatures and pressure. Chemical Communications. ISSN 1359-7345. 40. doi: 10.1039/d3cc00948c. Fulltekst i vitenarkiv Vis sammendrag

  Sending ethane over Cu-oxo sites in zeolites allows for the selective formation of ethylene in a stepwise reaction at mild conditions. Experimental results indicate that the reaction proceeds via the formation of ethanol intermediates.

• Kvande, Karoline; Mawanga, Moses; Prodinger, Sebastian; Solemsli, Bjørn Gading; Yang, Jia & Olsbye, Unni [Vis alle 9 forfattere av denne artikkelen] (2023). Microcalorimetry on Cu-MCM-22 Reveals Structure-Activity Relationships for the Methane-to-Methanol Reaction. Industrial & Engineering Chemistry Research. ISSN 0888-5885. 62(28), s. 10939–10950. doi: 10.1021/acs.iecr.3c00988. Fulltekst i vitenarkiv Vis sammendrag

  With a stepwise mechanism for direct methane activation to methanol (MTM) over Cu-zeolites, it is possible to produce methanol with high selectivity. With this study, we apply adsorption/desorption experiments with n-propylamine, NH3, and CH4 as powerful techniques to learn more about the acidity and nature of the Cu-sites within a hitherto untested material for MTM, namely, MCM-22. The Cu-exchanged zeolites have a moderate performance in MTM (∼0.10 molMeOH/molCu), and upon comparing to the activity of other zeolite frameworks, we use the results found for MCM-22 to search for structure–activity relationships. We show with CO-adsorption FT-IR spectroscopy experiments that there is more than one distinct Cu-site within MCM-22, where one of which is likely linked with inactive Cu species. NH3 adsorption/desorption experiments disclose that the Brønsted acid sites before Cu exchange are few and heterogeneous in strength, leading to a low number of C–H-activating Cu-oxo species.

• Kvande, Karoline; Garetto, Beatrice; Deplano, Gabriele; Signorile, Matteo; Solemsli, Bjørn Gading & Prodinger, Sebastian [Vis alle 11 forfattere av denne artikkelen] (2023). Understanding C-H activation in light alkanes over Cu-MOR zeolites by coupling advanced spectroscopy and temperature-programmed reduction experiments. Chemical Science. ISSN 2041-6520. doi: 10.1039/d3sc01677c. Fulltekst i vitenarkiv Vis sammendrag

  The direct activation of methane to methanol (MTM) proceeds through a chemical-looping process over Cu-oxo sites in zeolites. Herein, we extend the overall understanding of oxidation reactions over metal-oxo sites and C–H activation reactions by pinpointing the evolution of Cu species during reduction. To do so, a set of temperature-programmed reduction experiments were performed with CH4, C2H6, and CO. With a temperature ramp, the Cu reduction could be accelerated to detect changes in Cu speciation that are normally not detected due to the slow CH4 adsorption/interaction during MTM (∼200 °C). To follow the Cu-speciation with the three reductants, X-ray absorption spectroscopy (XAS), UV-vis and FT-IR spectroscopy were applied. Multivariate curve resolution alternating least-square (MCR-ALS) analysis was used to resolve the time-dependent concentration profiles of pure Cu components in the X-ray absorption near edge structure (XANES) spectra. Within the large datasets, as many as six different CuII and CuI components were found. Close correlations were found between the XANES-derived CuII to CuI reduction, CH4 consumption, and CO2 production. A reducibility–activity relationship was also observed for the Cu-MOR zeolites. Extended X-ray absorption fine structure (EXAFS) spectra for the pure Cu components were furthermore obtained with MCR-ALS analysis. With wavelet transform (WT) analysis of the EXAFS spectra, we were able to resolve the atomic speciation at different radial distances from Cu (up to about 4 Å). These results indicate that all the CuII components consist of multimeric CuII-oxo sites, albeit with different Cu–Cu distances.

• Deplano, Gabriele; Signorile, Matteo; Crocellà, Valentina; Porcaro, Natale Gabriele; Atzori, Cesare & Solemsli, Bjørn Gading [Vis alle 8 forfattere av denne artikkelen] (2022). Titration of Cu(I) Sites in Cu-ZSM-5 by Volumetric CO Adsorption. ACS Applied Materials & Interfaces. ISSN 1944-8244. 14(18), s. 21059–21068. doi: 10.1021/acsami.2c03370. Fulltekst i vitenarkiv Vis sammendrag

  Cu-exchanged zeolites are widely studied materials because of their importance in industrial energetic and environmental processes. Cu redox speciation lies at the center of many of these processes but is experimentally difficult to investigate in a quantitative manner with regular laboratory equipment. This work presents a novel technique for this purpose that exploits the selective adsorption of CO over accessible Cu(I) sites to quantify them. In particular, isothermal volumetric adsorption measurements are performed at 50 °C on a series of opportunely pre-reduced Cu-ZSM-5 to assess the relative fraction of Cu(I); the setup is fairly simple and only requires a regular volumetric adsorption apparatus to perform the actual measurement. Repeatability tests are carried out on the measurement and activation protocols to assess the precision of the technique, and the relative standard deviation (RSD) obtained is less than 5%. Based on the results obtained for these materials, the same CO adsorption protocol is studied for the sample using infrared spectroscopy, and a good correlation is found between the results of the volumetric measurements and the absorbance of the peak assigned to the Cu(I)–CO adducts. A linear model is built for this correlation, and the molar attenuation coefficient is obtained, allowing for spectrophotometric quantification. The good sensitivity of the spectrophotometric approach and the precision and simplicity of the volumetric approach form a complementary set of tools to quantitatively study Cu redox speciation in these materials at the laboratory scale, allowing for a wide range of Cu compositions to be accurately investigated.

• Kvande, Karoline; Prodinger, Sebastian; Schlimpen, Fabian; Beato, Pablo; Pale, Patrick & Chassaing, Stefan [Vis alle 7 forfattere av denne artikkelen] (2022). Copper-zeolites Prepared by Solid-state Ion Exchange - Characterization and Evaluation for the Direct Conversion of Methane to Methanol. Topics in catalysis. ISSN 1022-5528. doi: 10.1007/s11244-022-01763-7. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Direct conversion of methane to methanol (MTM) over Cu-zeolites is a so-called “dream reaction” for the chemical industry. There is still a lot that can be done in order to optimize the reaction by e.g. achieving a deeper understanding of the reaction mechanism and the nature of the Cu-sites. In this study, we investigated a solid-state ion exchange method to incorporate Cu I ions into zeolites (MOR, BEA, ZSM-5 and FAU), as a more scalable technique. The solid-state ion exchange led to a Cu/Al ration of about 0.8, however with a heterogeneous distribution of Cu. Regardless, Fourier transform-infrared spectroscopy still revealed that most Brønsted acid sites were exchanged in all four samples. Further, CH 4 -temperature programmed reaction experiments showed that some Cu-sites formed were reactive towards CH 4 , with Cu I -MOR and Cu I -FAU having the largest CH 4 consumption. Ultimately, the Cu I -zeolites were tested in the MTM reaction and proved capable of producing methanol, even without the presence of Brønsted sites. A MOR with lower Cu/Al ratio (0.30) was also tested for comparison, and as this sample obtained a much higher productivity than the Cu I -MOR with high Cu-loading (0.10 vs. 0.03 mol MeOH /mol Cu ), it was demonstrated that some fine-tuning is necessary to obtain the active Cu sites for methane activation.

• Kalantzopoulos, Georgios; Gama, Daniel Rojo; Pappas, Dimitrios; Dovgaliuk, Iurii; Olsbye, Unni & Beato, Pablo [Vis alle 9 forfattere av denne artikkelen] (2022). Real-time regeneration of a working zeolite monitored via operando X-ray diffraction and crystallographic imaging: how coke flees the MFI framework. Dalton Transactions. ISSN 1477-9226. 51(44), s. 16845–16851. doi: 10.1039/d2dt02845j. Fulltekst i vitenarkiv Vis sammendrag

  We have monitored the regeneration of H-ZSM-5 via operando time-resolved powder X-Ray diffraction (PXRD) coupled with mass spectroscopy (MS). Parametric Rietveld refinements and calculation of the extra-framework electronic density by differential Fourier maps analysis provide details on the mode of coke removal combined with the corresponding sub-unit cell changes of the zeolite structure. It is clear that the coke removal is a complex process that occurs in at least two steps; a thermal decomposition followed by oxidation. In a coked zeolite, the straight 10-ring channel circumference is warped to an oval shape due to structural distortion induced by rigid aromatic coke species. The data presented explain why the difference in length between the a-vector and the b-vector of the MFI unit cell is a robust descriptor for bulky coke, as opposed to the unit cell volume, which is affected also by adsorbed species and thermal effects. Our approach holds the promise to quantify and identify coke removal (and formation) in structurally distinct locations within the zeolite framework.

• Prodinger, Sebastian; Kvande, Karoline; Arstad, Bjørnar; Borfecchia, Elisa; Beato, Pablo & Svelle, Stian (2022). Synthesis-Structure-Activity Relationship in Cu-MOR for Partial Methane Oxidation: Al Siting via Inorganic Structure-Directing Agents. ACS Catalysis. 12(4), s. 2166–2177. doi: 10.1021/acscatal.1c05091. Fulltekst i vitenarkiv Vis sammendrag

  In the pursuit of controlling the propensity of Cu-mordenite (MOR) for the selective oxidation of CH4, we take a closer look at intrinsic zeolite parameters. Via synthesis design, we vary the relative proportion of Al situated near the 8-rings and 12-rings of MOR zeolite. This is accomplished using different Al sources impacting the local degree of silica dissolution and zeolite formation as evidenced by crystallization times and morphological differences. Interrogating the crystalline system with steric probe molecules in conjunction with spectroscopic techniques such as 1H magic angle spinning (MAS) NMR, infrared spectroscopy, as well as temperature-programmed desorption confirms discrete changes of the Al within the unit cell. The subsequent copper exchange allows for the generation of Cu-MOR materials of different inclinations for the activation of methane in the stepwise formation of MeOH. Here, an increasing degree of acid sites in more easily accessible locations (e.g., 12-ring) correlates with increasing maximum productivity toward MeOH at moderate exchange degrees. X-ray absorption spectroscopy supports this notion, finding a higher concentration of self-reduction-resistant framework-associated Cu2+ species, previously established as the active sites in the selective oxidation of CH4.

• Mortén, Magnus; Lanzac, Tomas Cordero; Cnudde, Pieter; Redekop, Evgeniy; Svelle, Stian & Speybroeck, Veronique Van [Vis alle 7 forfattere av denne artikkelen] (2021). Acidity effect on benzene methylation kinetics over substituted H-MeAlPO-5 catalysts. Journal of Catalysis. ISSN 0021-9517. 404, s. 594–606. doi: 10.1016/j.jcat.2021.11.002. Fulltekst i vitenarkiv Vis sammendrag

  Methylation of aromatic compounds is a key reaction step in various industrial processes such as the aromatic cycle of methanol-to-hydrocarbons chemistry. The study of isolated methylation reactions and of the influence of catalyst acidity on their kinetics is a challenging task. Herein, we have studied unidirectional metal-substituted H-MeAlPO-5 materials to evaluate the effect of acid strength on the kinetics of benzene methylation with DME. First-principle simulations showed a direct correlation between the methylation barrier and acid site strength, which depends on the metal substituent. Three H-MeAlPO-5 catalysts with high (Me = Mg), moderate (Me = Si) and low acidity (Me = Zr) were experimentally tested, confirming a linear relationship between the methylation activation energy and acid strength. The effects of temperature and reactant partial pressure were evaluated, showing significant differences in the byproduct distribution between H-MgAlPO-5 and H-SAPO-5. Comparison with propene methylation suggested that the Mg substituted catalyst is also the most active for the selective methylation of alkenes.

• Deplano, Gabriele; Martini, Andrea; Signorile, Matteo; Borfecchia, Elisa; Crocellà, Valentina & Svelle, Stian [Vis alle 7 forfattere av denne artikkelen] (2021). Copper Pairing in the Mordenite Framework as a Function of the CuI/CuII Speciation. Angewandte Chemie International Edition. ISSN 1433-7851. 60(49), s. 25891–25896. doi: 10.1002/anie.202109705. Fulltekst i vitenarkiv Vis sammendrag

  A series of gas-phase reactants is used to treat a Cu-exchanged mordenite zeolite with the aim of studying the influence of the reaction environment on the formation of Cu pairs. The rearrangement of Cu ions to form multimeric sites as a function of their oxidation state was probed by X-ray absorption spectroscopy (XAS) and also by applying advanced analysis through wavelet transform, a method able to specifically locate Cu–Cu interactions also in the presence of overlapping contributions from other scattering paths. The nature of the Cu-oxo species formed upon oxidation was further crosschecked by DFT-assisted fitting of the EXAFS data and by resonant Raman spectroscopy. Altogether, the CuI/CuII speciation clearly correlates with Cu proximity, with metal ion pairs quantitatively forming under an oxidative environment.

• Wragg, David Stephen; Kalantzopoulos, Georgios; Pappas, Dimitrios; Herrero, Irene Pinilla; Rojo-Gama, Daniel & Redekop, Evgeniy [Vis alle 10 forfattere av denne artikkelen] (2021). Mapping the coke formation within a zeolite catalyst extrudate in space and time by operando computed X-ray diffraction tomography. Journal of Catalysis. ISSN 0021-9517. 104, s. 1–6. doi: 10.1016/j.jcat.2021.07.001. Fulltekst i vitenarkiv Vis sammendrag

  We have used operando X-ray diffraction computed tomography (XRD-CT) analysed by rigorous crystallographic methods to reveal the behaviour of a zeolite/alumina based catalyst extrudate in the methanol-to-hydrocarbon reaction under working conditions (Treaction = 440 °C; ambient total pressure; WHSV = 12 gMeOH gextrudate−1 h−1). By doing so, we demonstrate that it is possible to precisely monitor how the cylindrical extrudate is deactivated during the process by gradual filling with coke from the outer surface towards the core. The operando data thus collected are simulated by a model taking both the reaction kinetics and the diffusion within the extrudate into account, and this analysis provides the tools required for future optimization of the degree of utilization of the catalyst. Both the operando experiment and post mortem XRD-CT of fully deactivated extrudates from a test reactor show clearly that the core of the catalyst body, around 1/3 of its volume, remains completely untouched by the reaction, even when the reactor output indicates zero activity.

• Herrero, Irene Pinilla; Borfecchia, Elisa; Cordero-Lanzac, Tomás; Mentzel, Uffe V.; Joensen, Finn & Lomachenko, Kirill A. [Vis alle 10 forfattere av denne artikkelen] (2021). Finding the active species: The conversion of methanol to aromatics over Zn-ZSM-5/alumina shaped catalysts. Journal of Catalysis. ISSN 0021-9517. 394, s. 416–428. doi: 10.1016/j.jcat.2020.10.024. Fulltekst i vitenarkiv
• Prodinger, Sebastian; Beato, Pablo & Svelle, Stian (2021). From Catalytic Test Reaction to Modern Chemical Descriptors in Zeolite Catalysis Research . Chemie Ingenieur Technik. ISSN 0009-286X. 93, s. 902–915. doi: 10.1002/cite.202000193. Fulltekst i vitenarkiv Vis sammendrag

  For the successful implementation of catalysts in industrial processes, three overall goals are optimized: activity, selectivity, and stability. This review will address the role of chemical descriptors in aiding and guiding the development of optimal zeolite catalyst designs with the above performance criteria in mind. It will focus on both gas‐phase and liquid‐phase catalysis with a special focus on methanol to hydrocarbon, and biomass valorization reactions. By way of preface, the research on constraint and spaciousness indices is discussed. These indices can be considered the original chemical descriptors of catalysis research.

• Gutterød, Emil Sebastian; Pulumati, S.H.; Kaur, Gurpreet; Lazzarini, Andrea; Solemsli, Bjørn Garding & Gunnæs, Anette Eleonora [Vis alle 13 forfattere av denne artikkelen] (2020). Influence of Defects and H2O on the Hydrogenation of CO2 to Methanol over Pt Nanoparticles in UiO-67 Metal-Organic Framework. Journal of the American Chemical Society. ISSN 0002-7863. 142(40), s. 17105–17118. doi: 10.1021/jacs.0c07153. Fulltekst i vitenarkiv Vis sammendrag

  In catalysts for CO2 hydrogenation, the interface between metal nanoparticles (NPs) and the support material is of high importance for the activity and reaction selectivity. In Pt NP-containing UiO Zr-metal–organic frameworks (MOFs), key intermediates in methanol formation are adsorbed at open Zr-sites at the Pt–MOF interface. In this study, we investigate the dynamic role of the Zr-node and the influence of H2O on the CO2 hydrogenation reaction at 170 °C, through steady state and transient isotope exchange experiments, H2O cofeed measurements, and density functional theory (DFT) calculations. The study revealed that an increased number of Zr-node defects increase the formation rates to both methanol and methane. Transient experiments linked the increase to a higher number of surface intermediates for both products. Experiments involving either dehydrated or prehydrated Zr-nodes showed higher methanol and methane formation rates over the dehydrated Zr-node. Transient experiments suggested that the difference is related to competitive adsorption between methanol and water. DFT calculations and microkinetic modeling support this conclusion and give further insight into the equilibria involved in the competitive adsorption process. The calculations revealed weaker adsorption of methanol in defective or dehydrated nodes, in agreement with the larger gas phase concentration of methanol observed experimentally. The microkinetic model shows that [Zr2(μ-O)2]4+ and [Zr2(μ–OH)(μ-O)(OH)(H2O)]4+ are the main surface species when the concentration of water is lower than the number of defect sites. Lastly, although addition of water was found to promote methanol desorption, water does not change the methanol steady state reaction rate, while it has a substantial inhibiting effect on CH4 formation. These results indicate that water can be used to increase the reaction selectivity to methanol and encourages further detailed investigations of the catalyst system.

• Suwardiyanto, S; Svelle, Stian & Howe, R. F. (2020). Chemical vapour deposition (CVD) of molybdenum into medium pore H-zeolites. IOP Conference Series: Materials Science and Engineering. ISSN 1757-8981. 763. doi: 10.1088/1757-899X/763/1/012056. Fulltekst i vitenarkiv
• Pappas, Dimitrios; Kvande, Karoline; Kalyva, Maria Evangelou; Dyballa, Michael Martin; Lomachenko, Kirill A. & Arstad, Bjørnar [Vis alle 11 forfattere av denne artikkelen] (2020). Influence of Cu-speciation in mordenite on direct methane to methanol conversion: Multi-Technique characterization and comparison with NH3 selective catalytic reduction of NOx. Catalysis Today. ISSN 0920-5861. 369, s. 1–7. doi: 10.1016/j.cattod.2020.06.050. Fulltekst i vitenarkiv Vis sammendrag

  The direct conversion of methane to methanol has the potential of substantially reducing methane emissions and flaring, as such a process might provide an alternative for remote natural gas locations. In this report, we investigate the performance of a range of Cu-exchanged mordenite zeolites as active materials for such a reaction, employing a stepwise protocol comprising activation in oxygen, methane loading, and methanol extraction with steam. We employ in situ HERFD XANES, FT-IR spectroscopy with CO as probe molecule, and XPS to investigate the Cu species in the zeolites during the process. The activity of the materials is investigated both for methane to methanol conversion and NH3 Selective Catalytic Reduction of NOx. It is demonstrated that, despite the fact that the same zeolite materials are active both for NH3-SCR and direct methane to methanol conversion, the active site requirements for these two reactions are different.

• Martini, Andrea; Signorile, Matteo; Negri, Chiara; Kvande, Karoline; Lomachenko, Kirill A. & Svelle, Stian [Vis alle 10 forfattere av denne artikkelen] (2020). EXAFS wavelet transform analysis of Cu-MOR zeolites for the direct methane to methanol conversion. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 22(34), s. 18950–18963. doi: 10.1039/d0cp01257b. Fulltekst i vitenarkiv
• Kvande, Karoline; Pappas, Dimitrios; Dyballa, Michael Martin; Buono, Carlo; Signorile, Matteo & Borfecchia, Elisa [Vis alle 13 forfattere av denne artikkelen] (2020). Comparing the Nature of Active Sites in Cu-loaded SAPO-34 and SSZ-13 for the Direct Conversion of Methane to Methanol. Catalysts. 10(191). doi: 10.3390/catal10020191. Fulltekst i vitenarkiv Vis sammendrag

  On our route towards a more sustainable future, the use of stranded and underutilized natural gas to produce chemicals would be a great aid in mitigating climate change, due to the reduced CO2 emissions in comparison to using petroleum. In this study, we investigate the performance of Cu-exchanged SSZ-13 and SAPO-34 microporous materials in the stepwise, direct conversion of methane to methanol. With the use of X-ray absorption spectroscopy, infrared (in combination with CO adsorption) and Raman spectroscopy, we compared the structure–activity relationships for the two materials. We found that SSZ-13 performed significantly better than SAPO-34 at the standard conditions. From CH4-TPR, it is evident that SAPO-34 requires a higher temperature for CH4 oxidation, and by changing the CH4 loading temperature from 200 to 300 ◦C, the yield (µmol/g) of SAPO-34 was increased tenfold. As observed from spectroscopy, both three- and four-fold coordinated Cu-species were formed after O2-activation; among them, the active species for methane activation. The Cu speciation in SAPO-34 is distinct from that in SSZ-13. These deviations can be attributed to several factors, including the different framework polarities, and the amount and distribution of ion exchange sites.

• Goodarzi, Farnoosh; Herrero, Irene Pinilla; Kalantzopoulos, Georgios N.; Svelle, Stian; Lazzarini, Andrea & Beato, Pablo [Vis alle 8 forfattere av denne artikkelen] (2020). Synthesis of mesoporous ZSM-5 zeolite encapsulated in an ultrathin protective shell of silicalite-1 for MTH conversion. Microporous and Mesoporous Materials. ISSN 1387-1811. 292. doi: 10.1016/j.micromeso.2019.109730. Fulltekst i vitenarkiv Vis sammendrag

  Coke formation is a major reason in deactivation of acidic zeolite catalysts in industrial processes such as methanol to hydrocarbons conversion. Protecting the surface of acidic zeolite with an inert porous shell can greatly hinder the coke formation on the surface, and hence boost the lifetime of the catalyst. In this work, a solid-state steam-assisted method for synthesis of such optimized protective shell (silicate-1, ~15 nm thickness) is designed. This general and simple protocol can be applied to acidic zeolite catalysts to improve their catalytic lifetime. The silicalite-1 shell is synthesized on mesoporous ZSM-5 zeolite to explore its catalytic activity in methanol to hydrocarbons conversion. XPS and TEM analysis confirm the coverage of mesoporous zeolite crystals by non-acidic shell. In addition, nitrogen physisorption shows the accessibility of mesoporous ZSM-5 via microporous silicalite-1 network. Applying this protective shell increases the lifetime of the catalyst by 100% and its conversion capacity by 130%, in comparison to mesoporous ZSM-5 without the shell. The controlled formation of thin layer of microporous silicalite-1 around mesoporous ZSM-5 crystals (without growth of individual silicalite-1) accounts for enhanced catalytic improvement.

• Dyballa, Michael Martin; Thorshaug, Knut; Pappas, Dimitrios; Borfecchia, Elisa; Kvande, Karoline & Bordiga, Silvia [Vis alle 12 forfattere av denne artikkelen] (2019). Zeolite surface methoxy groups as key intermediates in the stepwise conversion of methane to methanol. ChemCatChem. ISSN 1867-3880. 11(20), s. 5022–5026. doi: 10.1002/cctc.201901315. Fulltekst i vitenarkiv Vis sammendrag

  This contribution clarifies the overoxidation-preventing key step in the methane-to-methanol (MTM) conversion over copper mordenite zeolites. We followed the methane-to-methanol conversion over copper mordenite zeolites by NMR spectroscopy supported by DRIFTS to show that surface methoxy groups (SMGs) located at zeolite Brønsted sites are the key intermediates. The SMGs with chemical shift of 59 ppm are identical to those formed on a copper-free reference zeolite after reaction with methanol and react with water, methanol, or carbon monoxide to yield methanol, dimethyl ether, and acetate. This reactivity corroborates the location of SMGs at Brønsted sites. We find no evidence for stable SMGs directly at copper sites and explain mechanistically why H-form mordenites outperform their Na-form analogues. This finding is of interest for any future process that tries to trap the intermediate methane oxidation product towards methanol.

• Lomachenko, Kirill A.; Martini, A; Pappas, Dimitrios; Negri, Chiara; Dyballa, Michael Martin & Berlier, Gloria [Vis alle 12 forfattere av denne artikkelen] (2019). The impact of reaction conditions and material composition on the stepwise methane to methanol conversion over Cu-MOR: An operando XAS study. Catalysis Today. ISSN 0920-5861. 336, s. 99–108. doi: 10.1016/j.cattod.2019.01.040. Fulltekst i vitenarkiv
• Molino, Andrea; Holzinger, J.; Lukaszuk, Katarzyna Anna; Rojo-Gama, Daniel; Gunnæs, Anette Eleonora & Skibsted, J. [Vis alle 11 forfattere av denne artikkelen] (2019). Synthesis of ZSM-23 (MTT) zeolites with differentcrystal morphology and intergrowths: effects onthe catalytic performance in the conversion ofmethanol to hydrocarbons. Catalysis Science & Technology. ISSN 2044-4753. 9(23), s. 6782–6792. doi: 10.1039/c9cy01068h. Fulltekst i vitenarkiv Vis sammendrag

  A series of zeolite ZSM-23 samples prepared with different organic structure-directing agents, gave rise to crystalline phases, which show a large variety of particle dimensions. A detailed analysis of the structure of these materials revealed the presence of different levels of stacking fault defects when using different recipes. The effect of crystal size and morphology was investigated in the methanol to hydrocarbon reaction at 400 °C, showing a predominant production of hydrocarbons in the range C3–C6+ and negligible amount of aromatics (<3%) in all cases. More importantly, we show that methanol conversion and catalytic lifetime are strongly influenced by small differences in crystal size and morphology due to a preferential crystal growth along the microchannel direction.

• Gutterød, Emil Sebastian; Lazzarini, Andrea; Fjermestad, Torstein; Kaur, Gurpreet; Manzoli, Maela & Bordiga, Silvia [Vis alle 12 forfattere av denne artikkelen] (2019). Hydrogenation of CO2 to Methanol by Pt Nanoparticles Encapsulated in UiO-67: Deciphering the Role of the Metal−Organic Framework. Journal of the American Chemical Society. ISSN 0002-7863. 142(2), s. 999–999. doi: 10.1021/jacs.9b10873. Fulltekst i vitenarkiv Vis sammendrag

  Metal-organic frameworks (MOFs) show great prospect as catalysts and catalyst support materials. Yet, studies that address their dynamic, kinetic and mechanistic role in target reactions are scarce. In this study, an exceptionally stable MOF catalyst consisting of Pt nanoparticles (NPs) embedded in a Zr-based UiO-67 MOF was subject to steady-state and transient kinetic studies involving H/D and 13C /12C exchange, coupled with operando infrared spectroscopy and density functional theory (DFT) modeling, targeting methanol formation from CO2/H2 feeds at 170 C and 1-8 bar pressure. The study revealed that methanol is formed at the interface between the Pt NPs and defect Zr nodes, via formate species attached to the Zr nodes. Methanol formation is mechanistically separated from the formation of co-products CO and methane, except for hydrogen activation on the Pt NPs. Careful analysis of transient data revealed that the number of intermediates was higher than the number of open Zr sites in the MOF lattice around each Pt NP. Hence, additional Zr sites must be available to formate formation. DFT modelling revealed that Pt NP growth is sufficiently energetically favored to enable displacement of linkers and creation of open Zr sites during pretreatment. However, linker displacement during formate formation is energetically disfavored, in line with the excellent catalyst stability observed experimentally. Overall, the study provides firm evidence that methanol is formed at the interface of Pt NPs and linker-deficient Zr6O8 nodes resting on the Pt NP surface.

• Pappas, Dimitrios; Borfecchia, Elisa; Lomachenko, Kirill A.; Lazzarini, Andrea; Gutterød, Emil Sebastian & Dyballa, Michael Martin [Vis alle 14 forfattere av denne artikkelen] (2019). Cu-Exchanged Ferrierite Zeolite for the Direct CH4 to CH3OH Conversion: Insights on Cu Speciation from X-Ray Absorption Spectroscopy. Topics in catalysis. ISSN 1022-5528. 62(7-11). doi: 10.1007/s11244-019-01160-7. Fulltekst i vitenarkiv Vis sammendrag

  The direct stepwise transformation of CH4 to CH3OH over Cu-exchanged zeolites has been an intensively researched reaction as it can provide a solution for the utilization of this abundant feedstock. Up to date a commercial process is far from realization, which is why an understanding of the Cu speciation in zeolites as a function of reaction conditions as well as the development of a mechanistic view of the reaction are necessary to further advance the field. Herein we study Cu-exchanged ferrierite zeolite for the direct CH4 to CH3OH conversion by utilizing X-ray absorption spectroscopy (XAS), in order to assess the local structure and electronic properties of Cu through the reaction. A Cu-FER sample with a Cu/Al = 0.20 and Si/Al = 11 was subjected to three reaction cycles yielding ultimately 96 µmol CH3OH/gzeolite . Normalized to the Cu loading, this accounts for 0.33 mol CH3OH /molCu, making the sample comparable to very active Cu-MOR materials reported in the literature. During O2 activation, a transient self-reduction regime of CuII to CuI ions was identified; eventually leading to mostly framework interacting CuII species. CH4 loading leads to a reduction of these CuII containing species; which are finally partially reoxidized during H2O-assisted CH3OH extraction. The speciation after CH4 activation as well as H2O-assisted CH3OH extraction was assessed via linear combination fitting analysis of the XAS data.

• Holzinger, Julian; Nielsen, Malte; Beato, Pablo; Brogaard, Rasmus Yding; Buono, Carlo & Dyballa, Michael Martin [Vis alle 9 forfattere av denne artikkelen] (2019). Identification of Distinct Framework Aluminum Sites in Zeolite ZSM-23: A Combined Computational and Experimental 27Al NMR Study. Journal of Physical Chemistry C. ISSN 1932-7447. 123(13), s. 7831–7844. doi: 10.1021/acs.jpcc.8b06891. Fulltekst i vitenarkiv
• Dyballa, Michael Martin; Pappas, Dimitrios; Kvande, Karoline; Borfecchia, Elisa; Arstad, Bjørnar & Beato, Pablo [Vis alle 8 forfattere av denne artikkelen] (2019). On how copper mordenite properties govern the framework stability and activity in the methane-to-methanol conversion. ACS Catalysis. 9(1), s. 365–375. doi: 10.1021/acscatal.8b04437. Fulltekst i vitenarkiv
• Nielsen, Malte; Hafreager, Anders; Brogaard, Rasmus Yding; Wispelaere, Kristof De; Falsig, Hanne & Beato, Pablo [Vis alle 8 forfattere av denne artikkelen] (2019). Collective action of water molecules in zeolite dealumination. Catalysis Science & Technology. ISSN 2044-4753. 9(14), s. 3721–3725. doi: 10.1039/c9cy00624a. Fulltekst i vitenarkiv Vis sammendrag

  When exposed to steam, zeolite catalysts are irreversibly deactivated by loss of acidity and framework degradation caused by dealumination. Steaming typically occurs at elevated temperatures, making it challenging to investigate the mechanism with most approaches. Herein, we follow the dynamics of zeolite dealumination in situ, in the presence of a realistic loading of water molecules by means of enhanced sampling molecular dynamics simulations. H-SSZ-13 zeolite is chosen as a target system. Monte Carlo simulations predict a loading of more than 3 water molecules per unit cell at representative steaming conditions (450 °C, 1 bar steam). Our results show that a higher water loading lowers the free energy barrier of dealumination, as water molecules cooperate to facilitate hydrolysis of Al–O bonds. We find free energies of activation for dealumination that agree well with the available experimental measurements. Clearly, the use of enhanced sampling molecular dynamics yields a major step forward in the molecular level understanding of the dealumination; insight which is very hard to derive experimentally.

• Pappas, Dimitrios; Martini, Andrea; Dyballa, Michael Martin; Kvande, Karoline; Teketel, Shewangizaw & Lomachenko, Kirill A. [Vis alle 16 forfattere av denne artikkelen] (2018). The nuclearity of the active site for methane to methanol conversion in Cu-mordenite: a quantitative assessment. Journal of the American Chemical Society. ISSN 0002-7863. 140(45), s. 15270–15278. doi: 10.1021/jacs.8b08071. Fulltekst i vitenarkiv
• Campo, Pablo Del; Beato, Pablo; Rey, Fernando; Navarro, Maria Teresa; Olsbye, Unni & Lillerud, Karl Petter [Vis alle 7 forfattere av denne artikkelen] (2018). Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite. Catalysis Today. ISSN 0920-5861. 299, s. 120–134. doi: 10.1016/j.cattod.2017.04.042. Fulltekst i vitenarkiv Vis sammendrag

  In this work, an extensive investigation of the preparation of a large body of desilicated ZSM-22 zeolites and their basic characterization is presented. We investigate the effects of the properties of the starting zeolite, and we employ mixtures of NaOH with CTAB or TBAOH as well as subsequent acid washings to create mesoporous zeolites. Scanning and transmission electron microscopy and nitrogen adsorption revealed that the crystal morphology of the starting zeolite appears to be the dominant parameter which influences the mesopore generation. Mesopores were effectively created within the rod-like commercial crystallites, whereas the thinner dimensions of the needle-shaped particles of the lab-made zeolite represent an obstacle for an intra-mesopore creation. The alkaline, surfactant-assisted or combined NaOH/TBAOH desilication methods resulted in mesopores with different shape and size from the commercial zeolite. The sequential acid washing generally resulted in increased micropore volume with respect to the desilicated samples. Elemental analysis showed that extra-framework Al species were generated upon the desilication treatments, which are eventually removed by the acid treatment. The acidity studied by FTIR demonstrated that this occurs without a marked modification of the Brønsted acidity, whereas the concentration of surface silanol hydroxyl groups is increased. The comparison between the total Al concentration and the amount of Al in acidic sites quantified by pyridine adsorption shows that the acidity was recovered after the acid washing and suggests that original non-acidic Al species in the starting materials may have a role in the formation of both Lewis and extra-framework species upon desilication.

• Campo, Pablo Del; Olsbye, Unni; Lillerud, Karl Petter; Svelle, Stian & Beato, Pablo (2018). Impact of post-synthetic treatments on unidirectional H-ZSM-22 zeolite catalyst: Towards improved clean MTG catalytic process. Catalysis Today. ISSN 0920-5861. 299, s. 135–145. doi: 10.1016/j.cattod.2017.05.011. Fulltekst i vitenarkiv Vis sammendrag

  In the present study, a series of H-ZSM-22 mesoporous catalysts resulting from three different desilication treatments (NaOH treatment, treatment using mixtures of NaOH/CTAB and using mixtures of NaOH/TBAOH) and sequential acid leaching over two different (commercial and lab-made) microporous ZSM-22, were tested in the conversion of methanol to hydrocarbons. The influence of the post-synthetic treatments on the catalytic lifetime and product distribution was examined. The influence of the starting catalysts on the change in the catalyst properties was also reflected in the catalytic behaviour. An increase of about 10 times in total methanol conversion capacity with respect to the untreated catalyst was reached after the CTAB/NaOH and acid treatment over the commercial material, whereas a 17-fold increase in conversion capacity was achieved for the lab-made catalysts treated with NaOH and acid. The yield towards the aromatic-free C5+ alkene fraction was slightly increased after the post-synthetic treatments, up to 58% of clean gasoline product precursors. The correlations between porosity, acidity and total conversion capacity suggested a more efficient use of the hierarchical catalyst particle as a result of a synergetic effect of mesopore formation, enhanced accessibility to the micropores and acid sites, and increased adsorption and transport properties. Mechanistic information extracted from the analysis of the C3/C2 and ethene/2M2B ratios, suggested that the improved catalyst properties allow a longer propagation of the olefin cycle with reaction time.

• Dyballa, Michael Martin; Pappas, Dimitrios; Borfecchia, Elisa; Beato, Pablo; Olsbye, Unni & Lillerud, Karl Petter [Vis alle 8 forfattere av denne artikkelen] (2018). Tuning the material and catalytic properties of SUZ-4 zeolites for the conversion of methanol or methane. Microporous and Mesoporous Materials. ISSN 1387-1811. 265, s. 112–122. doi: 10.1016/j.micromeso.2018.02.004. Fulltekst i vitenarkiv Vis sammendrag

  This work describes the synthesis and investigation of improved SUZ-4 catalysts (SZR framework) and their application in methanol-to-olefins and methane-to-methanol conversion. We report boron containing, dealuminated and desilicated SUZ-4 catalysts. Ammonia and pyridine probe molecules enabled the assignment of acid site densities to the 10-MR and 8-MR pores, respectively. The difference in between the theoretically expected and the for the probes accessible acid site density is a good descriptor for the accessibility of pores and acid sites. The access to the 8-MR SUZ-4 pores is sterically hindered by counter ions as well as extra framework aluminum (EFAl) species that account for up to 15% of the aluminum. Dealumination and desilication were successfully applied to optimize the diffusion properties and resulted in outstandingly high BET surface area, nSi/nAl-ratios and potassium exchange degrees. The improved accessibility led to an up to 2-fold increased MTO conversion capacity of the catalysts. Cu-exchanged SUZ-4 was applied in the selective oxidation of methane to methanol. By operando X-ray absorption spectroscopy (XAS) we showed that CuII ions are mainly coordinated in 2Al sites of 6-MR motifs and inhibited for redox-reactions.

• Wispelaere, Kristof De; Martinez-Espin, Juan Salvador; Hoffmann, Max J; Svelle, Stian; Olsbye, Unni & Bligaard, Thomas (2018). Understanding zeolite-catalyzed benzene methylation reactions by methanol and dimethyl ether at operating conditions from first principle microkinetic modeling and experiments. Catalysis Today. ISSN 0920-5861. 312, s. 35–43. doi: 10.1016/j.cattod.2018.02.042. Fulltekst i vitenarkiv
• Signorile, Matteo; Rojo-Gama, Daniel; Bonino, Francesca; Svelle, Stian; Beato, Pablo & Bordiga, Silvia (2018). Operando UV-Raman study of the methanol to olefins reaction over SAPO-34: Spatiotemporal evolution monitored by different reactor approaches. Catalysis Today. ISSN 0920-5861. s. 1–7. doi: 10.1016/j.cattod.2018.11.065. Fulltekst i vitenarkiv
• Rojo-Gama, Daniel; Mentel, Lukasz; Kalantzopoulos, Georgios N.; Pappas, Dimitrios; Dovgaliuk, Iurii & Olsbye, Unni [Vis alle 11 forfattere av denne artikkelen] (2018). Deactivation of Zeolite Catalyst H-ZSM-5 during Conversion of Methanol to Gasoline: Operando Time- and Space-Resolved X-ray Diffraction. The Journal of Physical Chemistry Letters. 9(6), s. 1324–1328. doi: 10.1021/acs.jpclett.8b00094. Fulltekst i vitenarkiv Vis sammendrag

  The deactivation of zeolite catalyst H-ZSM-5 by coking during the conversion of methanol to hydrocarbons was monitored by high-energy space- and time-resolved operando X-ray diffraction (XRD) . Space resolution was achieved by continuous scanning along the axial length of a capillary fixed bed reactor with a time resolution of 10 s per scan. Using real structural parameters obtained from XRD, we can track the development of coke at different points in the reactor and link this to a kinetic model to correlate catalyst deactivation with structural changes occurring in the material. The “burning cigar” model of catalyst bed deactivation is directly observed in real time.

• Borfecchia, Elisa; Beato, Pablo; Svelle, Stian; Olsbye, Unni; Lamberti, Carlo & Bordiga, Silvia (2018). Cu-CHA – a model system for applied selective redox catalysis. Chemical Society Reviews. ISSN 0306-0012. 47(22), s. 8097–8133. doi: 10.1039/c8cs00373d. Fulltekst i vitenarkiv Vis sammendrag

  We review the structural chemistry and reactivity of copper-exchanged molecular sieves with chabazite (CHA) topology, as an industrially applied catalyst in ammonia mediated reduction of harmful nitrogen oxides (NH3-SCR) and as a general model system for red-ox active materials (also the recent results in the direct conversion of methane to methanol are considered). Notwithstanding the apparent structural simplicity of the material, a crystalline zeolite with only one crystallographically independent T site, the Cu-SSZ-13 catalyst reveals a high degree of complexity that has been decrypted by state of the art characterization tools. From the reviewed data, the following important aspects in the understanding of the Cu-SSZ-13 catalyst clearly emerged: (i) the structural dynamics of the Cu-species require precise control of the environmental conditions during activation and characterization; (ii) the availability of a large library of well-defined catalysts with different Si/Al and Cu/Al compositional ratios is key in unravelling the red-ox properties of the active Cu sites; (iii) a multi-technique approach is required, combining complementary techniques able to provide independent structural, electronic and vibrational information; (iv) synchrotron radiation based techniques (EXAFS, XANES, XES and time-resolved powder XRD) played a relevant role; (v) operando methodology (possibly supported by advanced chemometric approaches) is essential in obtaining structure–reactivity relations; (vi) the support of theoretical studies has been indispensable for the interpretation of the experimental output from characterization and for a critical assessment of mechanistic models. The old literature that classified Cu-exchanged zeolites in the category of single-site catalysts has been partially disproved by the recent advanced studies where it has been shown that the active site in the low temperature NH3-SCR catalyst is a mobile Cu-molecular entity that “lives in symbiosis” with an inorganic solid framework. Only in the high temperature NH3-SCR regime do the mobile Cu-species lose their ligands and find docking sites at the internal walls of the zeolite framework, thus reflecting the idea of a single-site catalyst. After a brief introduction, the review is divided into three main parts devoted to characterization (Section 2), reactivity (Section 3), and industrial applications (Section 4), followed by some concluding remarks and providing a perspective of the field.

• Pappas, Dimitrios; Borfecchia, Elisa; Dyballa, Michael Martin; Lomachenko, Kirill A.; Martini, Andrea & Berlier, Gloria [Vis alle 12 forfattere av denne artikkelen] (2018). Understanding and optimizing the performance of Cu‐FER for the direct CH4 to CH3OH conversion. ChemCatChem. ISSN 1867-3880. 11(1), s. 621–627. doi: 10.1002/cctc.201801542. Fulltekst i vitenarkiv
• Mortén, Magnus; Mentel, Lukasz; Lazzarini, Andrea; Pankin, Ilia A.; Lamberti, Carlo & Bordiga, Silvia [Vis alle 10 forfattere av denne artikkelen] (2018). A Systematic Study of Isomorphically Substituted H-MAlPO-5 Materials for the Methanol-to-Hydrocarbons Reaction. ChemPhysChem. ISSN 1439-4235. 19(4), s. 484–495. doi: 10.1002/cphc.201701024. Fulltekst i vitenarkiv
• Herrero, Irene Pinilla; Borfecchia, Elisa; Holzinger, Julian; Mentzel, Uffe V.; Joensen, Finn & Lomachenko, Kirill A. [Vis alle 13 forfattere av denne artikkelen] (2018). High Zn/Al ratios enhance dehydrogenation vs hydrogen transfer reactions of Zn-ZSM-5 catalytic systems in methanol conversion to aromatics. Journal of Catalysis. ISSN 0021-9517. 362, s. 146–163. doi: 10.1016/j.jcat.2018.03.032. Fulltekst i vitenarkiv Vis sammendrag

  Two series of Zn-ZSM-5 catalysts were prepared by ion exchanging two commercial zeolites with different Si/Al ratios (40 and 15) with increasing Zn loadings. The nature of the Zn sites in the zeolite was studied by spectroscopy using laboratory and synchrotron techniques. All the evidences suggest that catalytic activity is associated with [Zn(H2O)n(OH)]+ species located in the exchange positions of the materials with little or no contribution of ZnO or metallic Zn. The effect of Zn/Al ratio on their catalytic performance in methanol conversion to aromatics has been investigated. In all cases, higher Zn content causes an increase in the yield of aromatics while keeping the production of alkanes low. For similar Zn contents, high densities of Al sites favour the hydrogen transfer reactions and alkane formation whereas in samples with low Al contents, and thus higher Zn/Al ratio, the dehydrogenation reactions in which molecular hydrogen is released are favoured.

• Signorile, Matteo; Rojo-Gama, Daniel; Bonino, Francesca; Beato, Pablo; Svelle, Stian & Bordiga, Silvia (2018). Topology-dependent hydrocarbon transformations in the methanol to hydrocarbons reaction studied by operando UV-Raman spectroscopy. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 20(41), s. 26580–26590. doi: 10.1039/c8cp04240c. Fulltekst i vitenarkiv Vis sammendrag

  The methanol-to-hydrocarbons (MTH) reaction represents a versatile, industrially viable alternative to crude-oil based processes for the production of chemicals and fuels. In the MTH reaction, the shape selectivity of acidic zeolites is exploited to direct the synthesis towards the desired product. However, due to unavoidable side reactions occurring under processing conditions, all MTH catalysts suffer deactivation due to coke formation. Though it is likely that some common characteristics for carbon formation exist for all zeolite topologies, it has been proposed that the differences in shape selectivity among the different catalysts will also influence the individual deactivation mechanisms. As deactivating species are mostly aromatic compounds, highly methylated benzenes and/or polycyclic aromatic hydrocarbons (PAHs) have been discussed. In some cases, these can further grow to extended carbon structures. Here, we have investigated the hydrocarbon reactivities and carbon formation for five topologically different zeolite catalysts through an operando UV-Raman approach, taking advantage of the high sensitivity of this technique towards aromatic and other carbonaceous species. The combination of the spectroscopic tool with activity measurements allowed us to obtain valuable details and some general trends on the deactivation paths during MTH. This approach made accessible unique insight on the complex chemistry of MTH by allowing the real-time observation of hydrocarbon transformations typical for the peculiar topology of each catalyst, usually inaccessible by ex situ techniques.

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• Wragg, David Stephen; Wachs, Israel E.; Bañares, Miguel A. & Svelle, Stian (2023). Springer Handbook of Advanced Catalyst Characterization. Springer. ISBN 9783031071256. 1117 s. Fulltekst i vitenarkiv

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• Fjermestad, Torstein; Uglietti, Riccardo; Micale, Daniele; Bracconi, Mauro; Phan, Anh & Berdiell, Izar Capel [Vis alle 10 forfattere av denne artikkelen] (2024). Synergy between experiment and multiscale modelling to gain insight into the zeolite catalyzed methanol-to-DME reaction. Fulltekst i vitenarkiv
• Fjermestad, Torstein; Uglietti, Riccardo; Micale, Daniele; Bracconi, Mauro; Phan, Anh & Berdiell, Izar Capel [Vis alle 10 forfattere av denne artikkelen] (2024). Coupling kinetics and transport in a fixed-bed reactor from first-principles modelling. Fulltekst i vitenarkiv
• Seremak, Agnieszka Patrycja; Goeminne, Ruben; Berdiell, Izar Capel; Speybroeck, Veronique Van & Svelle, Stian (2024). Understanding Cation Mobility and Framework Flexibility in Na-Y Zeolite During Water Adsorption/Desorption via GCMC and Machine Learning Potentials. Fulltekst i vitenarkiv
• Fjermestad, Torstein; Uglietti, Riccardo; Micale, Daniele; Bracconi, Mauro; Phan, Anh & Striolo, Alberto [Vis alle 9 forfattere av denne artikkelen] (2023). Modelling the Methanol to Dimethyl Ether Reaction – Coupling Kinetics with Transport from CM to Å Scale. Fulltekst i vitenarkiv
• Svelle, Stian; Lundegaard, Lars Fahl; Beato, Pablo & Wragg, David Stephen (2023). Case Studies: Crystallography as a Tool for Studying Methanol Conversion in Zeolites, Springer Handbook of Advanced Catalyst Characterization. Springer. ISSN 9783031071256. s. 541–563. doi: 10.1007/978-3-031-07125-6_26. Fulltekst i vitenarkiv
• Fjermestad, Torstein; Uglietti, Riccardo; Micale, Daniele; Bracconi, Mauro; Phan, Anh & Striolo, Alberto [Vis alle 9 forfattere av denne artikkelen] (2023). Modelling the Methanol to Dimethyl ether reaction – coupling kinetics with transport from CM to Å scale. Fulltekst i vitenarkiv
• Svelle, Stian; Berdiell, Izar Capel; Wragg, David Stephen; Beato, Pablo & Lundegaard, Lars Fahl (2023). In situ and operando X-ray diffraction as a tool to monitor zeolite catalyst deactivation. Fulltekst i vitenarkiv
• Berdiell, Izar Capel; Wragg, David Stephen; Beato, Pablo; Lundegaard, Lars Fahl; Michel, Marco Di & Svelle, Stian (2023). Temperature Programmed Oxidation Probed with X-ray Diffraction Computed Tomography. Fulltekst i vitenarkiv
• Svelle, Stian (2023). Zeolite catalysis research at the University of Oslo. Fulltekst i vitenarkiv
• Fjermestad, Torstein; Uglietti, Riccardo; Micale, Daniele; Bracconi, Mauro; Phan, Anh & Striolo, Alberto [Vis alle 9 forfattere av denne artikkelen] (2023). Modelling the methanol to dimethyl ether reaction – coupling kinetic with transport from Å to cm scale. Fulltekst i vitenarkiv
• Kvande, Karoline; Garetto, Beatrice; Svelle, Stian & Borfecchia, Elisa (2022). Employing TPR to describe activity differences in the Methane-to-Methanol reaction over two different Cu-MOR. Fulltekst i vitenarkiv
• Kvande, Karoline; Bordiga, Silvia; Beato, Pablo & Svelle, Stian (2022). Cu-loaded mordenites for the activation of ethane to ethene in a stepwise, cyclic conversion protocol. Fulltekst i vitenarkiv
• Kvande, Karoline; Bordiga, Silvia; Beato, Pablo & Svelle, Stian (2022). Ethane to ethylene over Cu loaded zeolites. Fulltekst i vitenarkiv
• Solemsli, Bjørn Gading; Svelle, Stian; Prodinger, Sebastian & Kvande, Karoline (2022). Methylation of Lower alkenes though stepwise reaction with methane. Fulltekst i vitenarkiv
• Solemsli, Bjørn Gading; Kvande, Karoline; Prodinger, Sebastian & Svelle, Stian (2022). Fuels & Chemicals from Methane. Fulltekst i vitenarkiv
• Solemsli, Bjørn Gading; Svelle, Stian; Kvande, Karoline & Prodinger, Sebastian (2022). Direct Synthesis to Methanol from Methane over Cu-Zeolites. Fulltekst i vitenarkiv
• Fjermestad, Torstein; Uglietti, Riccardo; Micale, Daniele; Bracconi, Mauro; Phan, Anh & Striolo, Alberto [Vis alle 9 forfattere av denne artikkelen] (2022). Modelling the Methanol to Dimethyl ether reaction – coupling kinetics with transport from Å to CM scale. Fulltekst i vitenarkiv
• Svelle, Stian (2022). Monitoring the coking and deactivation of zeolite catalyst H-beta with X-ray diffraction. Fulltekst i vitenarkiv
• Kvande, Karoline; Prodinger, Sebastian; Borfecchia, Elisa; Garetto, Beatrice; Solemsli, Bjørn Gading & Signorile, Matteo [Vis alle 10 forfattere av denne artikkelen] (2022). Structural and mechanistic investigations of CuxOy- sites in zeolites and their role in the direct activation of lower alkanes. Fulltekst i vitenarkiv
• North, Erlend Tiberg; Chernyshov, Dmitry; Diadkin, Vadim; Koposov, Alexey; Svelle, Stian & Wragg, David Stephen (2022). Multivariate Analysis of Synchrotron X-ray Data for Battery Research. Fulltekst i vitenarkiv Vis sammendrag

  By utilizing multivariate analysis of x-ray operando data from working batteries one can separate and enhance scattering signals from specific components of the battery, identifying the critical responses that are connected to its performance and failure. This can enable faster and easier analysis of operando data, especially from complex materials that are difficult to analyze manually. In this poster I will present the preliminary results that we have obtained so far, focusing mainly on comparing analysis methods on simulated data sets, along with the current plan of the research project in my PhD.

• Berdiell, Izar Capel; Braghin, Giorgio Bruno; Cordero-Lanzac, Tomas; Beato, Pablo; Lundegaard, Lars Fahl & Wragg, David Stephen [Vis alle 8 forfattere av denne artikkelen] (2022). Tracking Structural Deactivation of H-Ferrierite Zeolite Catalyst during MTH with XRD. Fulltekst i vitenarkiv
• Berdiell, Izar Capel; König, Nico; Junge, Nicolai Haaber; Kalantzopoulos, Georgios; Beato, Pablo & Svelle, Stian [Vis alle 8 forfattere av denne artikkelen] (2022). Tracking deactivation level of zeolite H-beta catalysts with novel XRD models. Fulltekst i vitenarkiv
• Prodinger, Sebastian; Svelle, Stian & Beato, Pablo (2021). On the Role of Ions in the Formation of Zeolites. Fulltekst i vitenarkiv
• Fjermestad, Torstein; Micale, Daniele; Ahn, Phan; Striolo, Alberto; Stamatakis, Michail & Iacoviello, Francesco [Vis alle 8 forfattere av denne artikkelen] (2021). The effective diffusivity bridges the kinetics at the active sites and the fluid flow in the reactor. Fulltekst i vitenarkiv
• Kvande, Karoline; Svelle, Stian; Pappas, Dimitrios K; Borfecchia, Elisa; Martini, Andrea & Bordiga, Silvia [Vis alle 7 forfattere av denne artikkelen] (2021). Methane to methanol conversion over Cu-zeolites – structure performance relationships. Fulltekst i vitenarkiv
• Arstad, Bjørnar; Dyballa, Michael Martin; Thorshaug, Knut; Pappas, Dimitrios K; Borfecchia, Elisa & Kvande, Karoline [Vis alle 12 forfattere av denne artikkelen] (2020). Solid State NMR studies of the stepwise transformation of methane to methanol over Cu-Zeolites. Fulltekst i vitenarkiv
• Kvande, Karoline & Svelle, Stian (2020). New paths for “direct activation of lower alcanes”. Fulltekst i vitenarkiv
• Kvande, Karoline; Svelle, Stian & Beato, Pablo (2020). CH4-TPR: A good descriptor for optimizing the direct conversion of methane-to-methanol? Fulltekst i vitenarkiv
• Dyballa, Michael Martin; Pappas, Dimitrios; Borfecchia, Elisa; Kvande, Karoline; Bordiga, Silvia & Berlier, Gloria [Vis alle 11 forfattere av denne artikkelen] (2019). Cu-MOR applied in the stepwise methane-to-methanol conversion. Fulltekst i vitenarkiv
• Svelle, Stian (2019). Direct conversion of methane (to methanol): Is it feasible? Fulltekst i vitenarkiv
• Svelle, Stian (2019). Methane to methanol conversion over Cu-zeolites. Fulltekst i vitenarkiv
• Svelle, Stian (2019). Spatiotemporal studies of the deactivation of zeolites by coking during the conversion of methanol to hydrocarbons. Fulltekst i vitenarkiv
• Bjørgen, Morten; Eilertsen, Heidi; Gjengedal, Elin Lovise Folven; Maarten, Aerts & Svelle, Stian (2019). Bruk av kontrollkort i kjemilaboratoriet – hvorfor, hvordan og hvordan ikke. Kjemi. ISSN 0023-1983. 3, s. 22–27. Fulltekst i vitenarkiv
• Helgaker, Trygve; Svelle, Stian & Haugnes, Gunhild Merete (2019). Datakraft gir forskerne bedre intuisjon og flere ideer. [Journal]. Titan.uio.no. Fulltekst i vitenarkiv
• Svelle, Stian (2018). Zeolite catalysis at the University of Oslo. Fulltekst i vitenarkiv
• Svelle, Stian (2018). Zeolite research in the Catalysis group at the University of Oslo – Three case studies. Fulltekst i vitenarkiv
• Svelle, Stian (2018). Coking of zeolite ZSM-5 during the conversion of methanol to hydrocarbons monitored by X-ray diffraction tomography. Fulltekst i vitenarkiv
• Groppo, Elena; Svelle, Stian & Vos, Dirk De (2018). Understanding and Design Catalysts from Molecular to Material Scale: One of the Five Grand-Challenges for Catalysis at the 13th European Congress on Catalysis. Topics in catalysis. ISSN 1022-5528. 61(14), s. 1383–1384. doi: 10.1007/s11244-018-1034-y. Fulltekst i vitenarkiv
• Pappas, Dimitrios; Borfecchia, Elisa; Dyballa, Michael Martin; Berlier, Gloria; Bordiga, Silvia & Olsbye, Unni [Vis alle 8 forfattere av denne artikkelen] (2018). FOLLOWING O2-ACTIVATION OF CU-ZEOLITES WITH TIME-RESOLVED XAS. Fulltekst i vitenarkiv
• Pappas, Dimitrios; Borfecchia, Elisa; Berlier, Gloria; Beato, Pablo & Svelle, Stian (2018). Methane to Methanol over Cu-Zeolites: Establishing Structure-Activity Relationships. Fulltekst i vitenarkiv
• Pappas, Dimitrios; Borfecchia, Elisa; Dyballa, Michael Martin; Martini, Andrea; Lomachenko, Kirill A. & Berlier, Gloria [Vis alle 11 forfattere av denne artikkelen] (2018). Methane to Methanol over Cu-Zeolites: Establishing Structure-Activity Relationships. Fulltekst i vitenarkiv
• Olsbye, Unni; Mortén, Magnus; Mentel, Lukasz; Lazzarini, Andrea; Pankin, Ilya & Lamberti, Carlo [Vis alle 10 forfattere av denne artikkelen] (2018). On the influence of catalyst acid strength in the Methanol to Hydrocarbons (MTH) and related reactions. Fulltekst i vitenarkiv
• Njoroge, Peter Ng'ang'a; Olsbye, Unni; Prodinger, Sebastian & Svelle, Stian (2026). Rational Design of Mordenite: Linking Synthesis Parameters, Framework Properties, Copper Speciation and Methane-to-Methanol Performance. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  The selective conversion of methane to methanol (MTM) under mild conditions remains one of the major challenges in heterogeneous catalysis due to the C-H bond strength in methane and hence, the tendency of methanol to undergo overoxidation. Among the catalyst systems investigated for this transformation, Cu-exchanged zeolites, particularly Cu-mordenite (Cu-MOR), have emerged as promising materials because of their ability to stabilize reactive copper-oxo species within confined microporous environments. Despite extensive investigation, substantial differences in methanol productivity are reported for nominally similar Cu-MOR catalysts, highlighting the absence of consistent and transferable synthesis-structure-activity relationships. In particular, the influence of zeolite synthesis history and framework formation on copper speciation and subsequent catalytic performance remains insufficiently understood. This thesis addresses this challenge through a synthesis-driven investigation of mordenite zeolites, focusing on how hydrothermal synthesis parameters such as structure directing agents and aging time influence framework formation, aluminium siting, copper incorporation, and methane activation. Rather than relying on commercially sourced materials, all zeolites investigated in this work were synthesized in-house under systematically controlled conditions. The work specifically examines the influence of inorganic structure-directing agents (ISDA), gel aging, and isomorphous framework substitution on the resulting framework topology, pore architecture, acidity, and local coordination environments. A combination of advanced characterization techniques, including diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), solid-state nuclear magnetic resonance (ssNMR), Raman spectroscopy, nitrogen adsorption, and MTM testing, was employed to establish direct synthesis-structure-activity relationships. The obtained results demonstrate that variations in synthesis conditions lead to significant differences in aluminium distribution and framework ordering, which subsequently govern copper speciation as well as the nature of the active Cu species. The findings reveal that synthesis-induced framework variations strongly influence the stabilization of mono-, and di-meric, copper species within the MOR framework and thereby determine extent of methane activation and thus methanol productivity. Differences in aging conditions and inorganic structure-directing agents were found to alter aluminium siting and Brønsted acidity, leading to measurable differences in copper incorporation and catalytic behaviour during methane-to-methanol conversion. Furthermore, isomorphous site substitution using heteroatoms such as Ga and Fe demonstrated how subtle modifications to framework composition influence crystallinity, copper speciation, and catalytic performance. Collectively, the results demonstrate that methane-to-methanol performance in CuMOR cannot be optimized solely through adjustment of copper loading or reaction conditions but is intrinsically governed by the synthesis history and directly linked to the framework formation. The zeolite framework must therefore be regarded not as passive support, but rather as an integral component of the catalytic system that dictates active-site formation, copper reactivity, and methane activation behaviour. Ultimately, this work establishes a unified synthesis-framework-activity relationship for Cu-MOR based materials and provides design principles for the rational development of improved methane activation materials and other framework-controlled catalytic systems.

• Kvande, Karoline & Svelle, Stian (2023). Compositional and Mechanistic Studies of Cu-zeolites for the Direct Activation of Lower Alkanes. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Due to poor access and energy-intensive conversion reactions, large reservoirs of natural gas are underutilized. Natural gas and biogas mainly contain small and stable hydrocarbons (light alkanes) and could be a more sustainable resource in the nearest future for the chemical industry, compared to coal and oil. However, due to the stability of alkanes, it is notoriously difficult to make specific products, because, in a reaction, the products are usually more reactive, and unwanted by-products are formed. With the help of activity testing and multiple characterization techniques, we have obtained insight into a direct, but stepwise pathway to convert alkanes to functionalized products for the industry that is potentially less energy-demanding than the existing ones. The stepwise pathway proceeds over oxidized Cu ions anchored to porous materials (zeolites) that hinder the reactants and products from interacting. With this approach, there is almost no over-oxidation, although, the product yield per time from this reaction is low. Accordingly, our focus has been on exploring different parts of the reaction to understand the individual steps and how they can be improved. We have obtained more insight into the Cu speciation and found important activity relationships with both zeolite structure and Cu ion reducibility.

• Bygdnes, Odd Reidar; Svelle, Stian & Prodinger, Sebastian (2022). Synthesis of mordenite zeolite for the conversion of methane to methanol. Universitetet i Oslo. Fulltekst i vitenarkiv
• Grimstvedt, Kristoffer Flem & Svelle, Stian (2022). A study of zeolite’s catalytic deactivation and its effect on the crystal structure. Universitetet i Oslo. Fulltekst i vitenarkiv
• Gutterød, Emil Sebastian; Olsbye, Unni; Svelle, Stian & Redekop, Evgeniy (2020). On the Hydrogenation of CO2 over Pt Functionalized UiO-67 Metal-Organic Frameworks. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Hydrogenation of CO2 is receiving increasing attention as a sustainable way of producing value-added products that are today produced from fossil fuels. The overall aim of his thesis has been to gain fundamental insights into the CO2 hydrogenation reaction over Pt functionalized UiO-67 Zr-metal-organic frameworks (MOF). Activity measurements after activating the material in different H2 concentrations revealed that the catalytic activity is dependent on the degree of Pt reduction and aggregation from framework bound Pt(II) moieties into nanoparticles (NP), a main reason being the incapability of UiO-67 alone to dissociate H2. The Pt NPs grow larger than the pore size of the MOF structure and disrupts the lattice locally. This causes the formation of open Zr-sites at the Pt–MOF interface. Overall, the catalyst exhibits excellent structural and catalytic stability, even after activation at 350 °C and prolonged operation under reaction conditions for 52 hours. CO formation dominates under all tested conditions; however, substantial methanol formation is observed at lower temperatures (170 °C) and moderate pressures (8 bar). Evidence from classical kinetic experiments and H/D exchange suggest that CO desorption is rate limiting in CO formation and that methanol is mainly a primary reaction product. The temporal evolution of H/D exchange in formate at open Zr-sites at the Pt–MOF interface closely follows that of methanol in gas-phase. Combined with a reasonable agreement between the number of intermediates in methanol formation and the estimated number of sites accessible for formate coordination, the results strongly suggest that methanol is formed from hydrogenation of CO2 via a formate intermediate at open Zr-sites at the Pt–MOF interface. Through rational MOF design we further show that defectivity is directly related to the number of active sites in methanol formation. Lastly, it is found that the hydration state of the Zr-node and the presence of H2O in gas-phase have a substantial influence on methanol formation and adsorption/desorption. In total, the work provides mechanistic insights into CO2 hydrogenation over UiO-67-Pt and the dynamic role of the MOF lattice in the reaction.

• Kumar, Sushant; Svelle, Stian & Lillerud, Karl Petter (2020). Potentiometric acid-base titration as a tool to characterize porous solid acids. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Potentiometric acid-base titration was introduced to measure pKa values (Brønsted acidity) of protons in Zr_6-based metal-organic frameworks (MOFs), including UiO-type MOFs and MOF-808. The pKa values of three typical types of proton present in these MOFs, μ_3-OH, Zr - OH_2, and Zr – OH were evaluated. The two latter protons are assumed to mainly originate from missing linker. From structural characterization using techniques such as TGA, NMR, and EDS, it seemed to not entirely be the case, since standard UiO-66-BDC was observed to not have any defects from the linkers, and the small amount of chloride detected may originate from the pores of the material rather than being part of the structure. Also, one of the two standard UiO-67s (UiO-67-400) which was amorphous, could seemingly detect protons similar to the other crystalline UiO-67-PM MOF and literature. This weakens the hypothesis that potentiometric acid-base titration is a good method to characterize MOFs. All materials were characterized by PXRD, SEM/EDS, TGA, and N2-adsorption. Additionally, the acidic properties of the titrated samples were compared with MP-AES, EDS, and TPD for zeolites and FT-IR for MOFs. FT-IR was applied to discover the same Brønsted acids that were detected by potentiometric acid-base titration. The μ_3-OH proton could be found with both techniques, but the others could not be detected by the preliminary FT-IR measurements that were carried out. Potentiometric acid-base titration was also used to find the available acid site density for commercial zeolites, involving H-USY (FAU), H-BEA-25 (*BEA), and H – β (*BEA), and H-ZSM-5 (MFI). MP-AES and EDS revealed a higher Si/Al ratio (lower Al content) in all the zeolites compared with the value that was provided by the suppliers. This would predict that fewer amount of acid sites would be detected when using potentiometric titration and TPD, which appeared to be the case. The results indicated good agreement between potentiometric acid-base titration and TPD since the measured density acid sites (μmol/g) showed values comparable to each other. This was especially the case for zeolites with low Al content.

• Kvande, Karoline; Svelle, Stian; Dyballa, Michael Martin & Pappas, Dimitrios (2019). A Study of Cu-loaded SAPO-34 for the Direct Conversion of Methane to Methanol. Universitetet i Oslo. Fulltekst i vitenarkiv
• Ibishi, Diamanta & Svelle, Stian (2019). The conversion of methanol to olefins reaction has been tested over synthesized and commercial SAPO-11, where the supplied and synthesized materials inhibit different morphology, surface area, and acid sites density. The synthesized samples were synthesized with the hydrothermal method and the effect of static and rotational crystallization in a temperature range of 150 to 180 °C were investigated for prepared synthesis mixtures. All samples were characterized by PXRD, SEM, TGA, N2 physisorption. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  The conversion of methanol to olefins reaction has been tested over synthesized and commercial SAPO-11, where the supplied and synthesized materials inhibit different morphology, surface area, and acid sites density. The synthesized samples were synthesized with the hydrothermal method and the effect of static and rotational crystallization in a temperature range of 150 to 180 °C were investigated for prepared synthesis mixtures. All samples were characterized by PXRD, SEM, TGA, N2 physisorption, MP-AES, EDS, and CO-FTIR. The results obtained, indicated a systematic decrease in the measured diameter (µm) for the synthesized SAPO-11 aggregates. The trend was reported as a function of increased temperature under both static and rotational conditions. This screening also revealed that the most uniform SAPO-11 aggregates were obtained at high crystallization temperature. Elemental analysis showed the silicon content for the as-synthesized SAPO-11 was 10 times lower than the supplied SAPO-11. This finding was linked to the difference in catalytic activity observed between commercial SAPO-11 and synthesized SAPO-11 at 180 °C. Performance test revealed methanol to olefins conversion was feasible for both supplied and synthesized samples. The supplied SAPO-11 sample showed an initial higher methanol conversion towards hydrocarbon formation, whilst the in-house synthesized samples inhibited a similar behavior at lower conversion percentages. All tested samples obtained highest selectivities toward C5+ hydrocarbons. Nevertheless, synthesized samples proved to be more stable and selective towards the C2-C4 hydrocarbons compared to the commercial sample.

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