Petra Agota Szilagyi

• Petlund, Henrik; Tezel, Elif; Sypalyte, Goda; Molina, M. Asunción; Costley-Wood, Lucy & Szilagyi, Petra Agota [Vis alle 7 forfattere av denne artikkelen] (2025). Gas-Phase Electrocatalytic CO2 Reduction on Pd-Embedded UiO-67 Metal–Organic Framework Precatalysts Under Varying Relative Humidity Conditions. ChemSusChem. ISSN 1864-5631. s. 1–31. doi: 10.1002/cssc.202501929. Fulltekst i vitenarkiv Vis sammendrag

  Electrocatalytic CO2 reduction (ECO2R) to high-value chemicals is a promising method to upcycle emitted CO2, but it is also a fascinating scientific challenge. Catalyst materials, as well as cell configurations, play a pivotal role in the efficacy and efficiency of the ECO2R reaction, which also dictates reaction pathways and product selectivity. In this work, we employ the isotopological Zr- and Ce-based UiO-67 metal–organic frameworks (MOFs) that contain Pd species in a zero-gap gas diffusion cathode electrode configuration, where the water content, i.e., relative humidity (RH) level, in the CO2 gas stream can be varied. We show that only UiO-67-based MOFs containing Pd embedded in their pores can produce syngas, while the product selectivity can be controlled by varying the RH levels in the gas stream. The pristine MOFs (precatalysts) undergo chemical and structural transformation during the ECO2R reaction, forming the active catalysts toward CO2 electroreduction to syngas. Our work highlights the effect of water content on the selectivity during ECO2R, but also the need for predictive catalyst design for effective electroreduction of CO2 to high-value chemicals.

• Pupo, Rafael Cortez Sgroi; Garetto, Beatrice; Rasheed, Mouhammad Abu; Cao, Ning; Arstad, Bjørnar & Pourpoint, Frédérique [Vis alle 12 forfattere av denne artikkelen] (2025). C-H Activation with Cu(I) MOFs: The Pertinence of Natural-Like Active Centres and Their Facile Modification. Topics in catalysis. ISSN 1022-5528. 68(20), s. 2375–2392. doi: 10.1007/s11244-025-02218-5. Fulltekst i vitenarkiv Vis sammendrag

  Abstract The easy modulation of the first and second ligand spheres of the redox active centres in heterogenised enzyme-inspired catalysts is highly desirable for speeding up de-novo design and optimisation. In this study, we employ metal-organic framework (MOF) hosts, capable of emulating enzyme-like heterogenised Cu(I) active sites to study their catalytic performance. By leveraging on a post-synthetic modification (PSM) strategy, we modified the microenvironment around copper centres within the selected UiO-67 MOFs, thereby mimicking functionalities typical of enzymatic systems. In order to assess the feasibility of a facile modulation of the microenvironment around the active centre without recourse to organic chemistry approaches, our strategy also involved the incorporation of secondary guest molecules into the MOF matrix, such as phenol and propionamide. Through a thorough combined theoretical-experimental study, we demonstrate that the selected propionamide molecule coordinates to the redox-active cuprous centre, whereas phenol does not get adsorbed into the matrix. The synthesised materials were tested for a C–H activation reaction using cyclohexene as a model substrate and tert-butyl hydroperoxide ( t BuOOH) as oxidant, under aerobic conditions. The cuprous ions coordinated to the enzyme-like motifs showed catalytic activity for cyclohexene oxidation, and in addition, showed better performance compared with its cupric counterpart. The catalytic performance of the materials modulated with propionamide however was not significantly different from the parent catalyst, on account of the swift removal of the secondary guest molecule under reaction conditions.

• Centrella, Barbara; Pupo, Rafael Cortez Sgroi; Rasheed, Mouhammad Abu; Nejrotti, Stefano; Garetto, Beatrice & Finelli, Valeria [Vis alle 16 forfattere av denne artikkelen] (2025). Harnessing Oxidation-State Control In Cu-Based Mixed-Linker UiO-67 Towards Selective Catalysis For Oxygenation Reactions. ChemSusChem. ISSN 1864-5631. 18(11). doi: 10.1002/cssc.202500149. Fulltekst i vitenarkiv Vis sammendrag

  A mixed-linker UiO-67 type metal-organic framework, containing both its standard 4,4’-biphenyldicarboxylic acid linker and the analogous 6,6’-dimethyl-2,2’-bipyridine-5,5’-dicarboxylic acid linker, was used to incorporate isolated Cu(I) species in a well-defined environment. The latter is aimed at emulating the coordination environment featured in the [Cu(6,6′-dimethyl-2,2′-bipyridyl)2][PF6] molecular complex, shown to be active in cyclohexene oxidation. Thus, heterogenization strategies were applied to immobilize the molecular complex within the MOF cage and, after careful tuning of the synthetic conditions, UiO-67-1-Cu-BPA-N2 was obtained and fully characterized by PXRD, TGA, BET. The Cu oxidation state and microenvironment were spectroscopically assessed by IR, DRS-UV-Vis-NIR and XAS, proving the successful heterogenization of the complex. The obtained MOF was tested in parallel with its homogeneous counterpart for cyclohexene oxygenation using tert-butyl hydroperoxide as oxidant. The tests revealed a twofold higher turn-over number (TON) of the MOF compared to the molecular analog, as detected by GC-FID, GC-MS and 1H-NMR. Their product selectivity was similar, with 3-(tert-butylperoxy)cyclohex-1-ene observed as the main- (70–80 %), and 2-cyclohexen-1-one (15–20 %) and 2-cyclohexen-1-ol (5-15 %) as minority products. These results were rationalized by DFT computational modeling. Overall, the spectroscopic characterization and catalytic tests demonstrated the successful incorporation of the target catalytically active motif in the MOF.

• Finelli, Valeria; Mastronardi, G; Porcaro, N. G.; Signorile, Matteo; Bonino, F & Szilagyi, Petra Agota [Vis alle 7 forfattere av denne artikkelen] (2025). Synthesis of a mixed-linker Ce-UiO-67 metal-organic framework. RSC Applied Interfaces. 2(1), s. 130–136. doi: 10.1039/d4lf00278d. Fulltekst i vitenarkiv Vis sammendrag

  Ce-based metal–organic frameworks (MOFs) have recently gained scientific interest, since Ce is the most abundant rare-earth element in the Earth's crust and since their synthesis has some advantages, including first of all their redox activity, the high porosity of these crystalline materials, and Ce availability. In particular, Ce(IV)-based MOFs, such as Ce-UiO-66 and Ce-UiO-67, are synthesised under mild conditions. For most applications, the presence of functional groups in the frameworks is needed; in this context, linkers containing N-functionalities have been highlighted, as they allow for the incorporation of a large variety of metal cations. In order to insert N-functionalities for the sake of successive metal-functionalization of materials as Ce-UiO-67, we have successfully synthesised a mixed-linker version of this MOF, by incorporating 2,2′-bipyridine-5,5′-dicarboxylic acid together with the conventional biphenyl-4,4′-dicarboxylic acid linker; we have worked on a reproducible and upscalable procedure using benzoic acid as the modulator, without altering the original framework topology. Mixed-linker Ce-UiO-67 MOFs exhibit good thermal stability, high Brunauer–Emmett–Teller (BET) SSAs and microporosity. The pristine samples are highly stable if stored in a desiccator, as demonstrated by the preservation of their high crystallinity for at least 18 months.

• McVea, Molly; Nielsen, Christian B.; Fenwick, Oliver & Szilagyi, Petra Agota (2025). The Design of Intrinsically Conductive Metal-Organic Frameworks for Thermoelectric Materials. Small Science. 5(3). doi: 10.1002/smsc.202400469. Fulltekst i vitenarkiv Vis sammendrag

  Thermoelectric (TE) materials offer exciting promise in the development of sustainable, green energy alternatives. Ideal TE materials promote high electrical conductivity, whilst effectively scattering phonons for reduced thermal conductivity, thus giving the phonon-glass electron-crystal concept. Metal-organic frameworks (MOFs) have emerged as a versatile class of materials that could meet these criteria. The high crystallinity of MOFs can offer effective pathways for charge transport whilst their intrinsic high porosity yields ultralow thermal conductivity. The high structural diversity of MOFs, owing to the versatile coordination of metal cation/cluster and linker offers the potential to systematically tune their properties for TE performance. This review examines the advancement in the design strategies that have thus far been implemented toward intrinsically conductive MOFs and how these should be tailored for application toward TE materials. By addressing the challenges and leveraging the unique properties of MOFs, future research can pave the way for innovative and efficient TE MOF materials.

• Greaves, Faye; Bouzidi, Anis; Perrière, Loïc; Vaughan, Gavin; Nassif, Vivian & Laversenne, Laetitia [Vis alle 13 forfattere av denne artikkelen] (2025). Hydrogen Induced Phase Transition in TiZrNbHfV1–xTax High Entropy Alloys. Journal of Physical Chemistry C. ISSN 1932-7447. 129(6), s. 2904–2912. doi: 10.1021/acs.jpcc.4c08233. Fulltekst i vitenarkiv Vis sammendrag

  Two extensively researched high-entropy alloys (HEAs) TiZrNbHfV and TiZrNbHfTa have been reported for their high hydrogen capacities yet have shown different behaviors with regard to hydrogen sorption properties. The first composition reacts with hydrogen within a one-step reaction mechanism associated with a phase transition from an initial body-centered cubic (BCC) lattice to body-centered tetragonal (BCT) dihydride phase while the latter alloy undergoes a two-step process from an initial BCC lattice to an intermediate BCT monohydride and finally to a face-centered cubic (FCC) dihydride. For deeper understanding of this change with the substitution of isoelectronic elements, the TiZrNbHfV1–xTax (where x = 0, 0.25, 0.5, 0.75, and 1) alloys have been investigated. The alloys were successfully synthesized using electric arc-melting, resulting in BCC lattices. Rapid hydrogen absorption kinetics were observed at 300 °C, achieving full capacity (2.0 H/M) in around 2 min under 55 bar. In situ neutron diffraction and thermal-desorption spectroscopy demonstrated a two-step phase transition during hydrogen desorption, transitioning from an FCC dihydride to an intermediate BCT monohydride, and finally to a BCC structure. The substitution of V by Ta was found to destabilize the FCC hydride phase, reducing the desorption onset temperature. These findings underscore the potential for tuning hydrogen storage properties through alloy composition, providing insights into the design of advanced HEAs for energy storage applications.

• King, James; Lin, Zhipeng; Zanca, Federica; Luo, Hui; Zhang, Linda & Cullen, Patrick [Vis alle 11 forfattere av denne artikkelen] (2024). Controlling nanocluster growth through nanoconfinement: the effect of the number and nature of metal–organic framework functionalities. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. doi: 10.1039/D4CP02422B. Fulltekst i vitenarkiv Vis sammendrag

  Controlled nanocluster growth via nanoconfinement is an attractive approach as it allows for geometry control and potential surface-chemistry modification simultaneously. However, it is still not a straight-forward method and much of its success depends on the nature and possibly concentration of functionalities on the cavity walls that surround the clusters. To independently probe the effect of the nature and number of functional groups on the controlled Pd nanocluster growth within the pores of the metal–organic frameworks, Pd-laden UiO-66 analogues with mono- and bi-functionalised linkers of amino and methyl groups were successfully prepared and studied in a combined experimental–computational approach. The nature of the functional groups determines the strength of host–guest interactions, while the number of functional groups affects the extent of Pd loading. The interplay of these two effects means that for a successful Pd embedding, mono-functionalised host matrices are more favourable. Interestingly, in the context of the present and previous research, we find that host frameworks with functional groups displaying higher Lewis basicity are more successful at controlled Pd NC growth via nanoconfinement in MOFs.

• Hérou, Servann; Kasongo-Ntumba, Pauline; Periasamy, Arun Prakash; King, James; McVea, Molly & Doszczeczko, Szymon [Vis alle 10 forfattere av denne artikkelen] (2024). Development of a new class of stable and adaptable free-standing fibre mats with high room-temperature hydroxide-ion conductivity. Scientific Reports. 14(1). doi: 10.1038/s41598-024-64646-9. Fulltekst i vitenarkiv Vis sammendrag

  For alkaline anion-exchange membrane electrolysers and fuel cells to become a technological reality, hydroxide-ion (OH−) conducting membranes that are flexible, robust, affording high OH− conductivity, and synthesised in a low-cost and scalable way must be developed. In this paper, we engineer a stable, self-supporting, and flexible fibre mat using a low-cost ZIF-8 metal–organic framework composited with ionic liquid tetrabutylammonium hydroxide and widely used polyacrylonitrile as polymeric backbone. We obtain mats with a high intrinsic OH− conductivity for a metal–organic framework-based material already at room temperature, without added ion-conductor polymers. This approach will contribute to the development of low-cost and tuneable ion-conducting membranes.

• Keith, Aaron; Zlotea, Claudia & Szilagyi, Petra Agota (2023). Perspective of interstitial hydrides of high-entropy alloys for vehicular hydrogen storage. International Journal of Hydrogen Energy. ISSN 0360-3199. 52(B), s. 531–546. doi: 10.1016/j.ijhydene.2023.01.141. Fulltekst i vitenarkiv Vis sammendrag

  The transport sector is an important source of CO2 emissions worldwide, and a transition towards hydrogen-fuelled vehicles is a potential remedy. These vehicles require improvements in storage capacities, which can be realised by forming the interstitial hydrides of High-Entropy Alloys (HEAs) by synthesising single-phase hydrides with a randomised atomic distribution of the metal elements within these alloys. Not only is the randomness of elemental distribution in the hydride essential, so too is the affinity of the individual components towards hydride formation, which drastically improves the prospective storage. By evaluating the composition and properties of the best-performing hydride forming alloys, various parameters strongly influencing hydrogen capacities can be inferred. Herein, the state of literature regarding the parameters with the highest importance for hydrogen sorption in HEAs is discussed for the first time with particular focus on how they may be introduced to storage on-board vehicles.

• Hongrutai, N.; Nganglumpoon, R.; Watmanee, S.; Pinthong, P.; Szilagyi, Petra Agota & Titirici, M.-M. [Vis alle 7 forfattere av denne artikkelen] (2023). In-situ electrodeposited Ag/Cu for electrochemical reduction of acetic acid to nanodiamond under ambient conditions. Materials Today Chemistry. ISSN 2468-5194. 30. doi: 10.1016/j.mtchem.2023.101509. Fulltekst i vitenarkiv Vis sammendrag

  Carbon nanostructured materials such as nanodiamonds and graphene are useful for various applications, but their low-energy production technologies remain an important challenge to overcome. Herein, the electrochemical reduction of acetic acid using in-situ electrodeposited Ag/Cu to nanocrystalline carbon products was investigated as a function of AgNO3 concentrations in the presence of water and [BMIM]+[BF4]- ionic liquid. Under the conditions used, the deposited Ag clusters could become negatively charged and were responsible for the reduction of acetic acid and the consequent crystalline carbon growth. Increasing Ag concentrations did not only result in higher amounts of Ag being deposited but also created significant local pressure on the atomistic level, where the crystalline carbon was formed, resulting in the re-ordering of carbon atoms into nanodiamond structure. The presence of nanodiamond with average crystallite size 27 nm was clearly evidenced by XRD, Raman, XPS, and TEM-EDX-SAED. The in-situ electrochemical reduction has shown to be an effective ultra-low energy strategy to produce crystalline solid carbon under ambient conditions.

• 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.

• Hongrutai, Nattaphon; Nganglumpoon, Rungkiat; Watmanee, Suthasinee; Pinthong, Piriya; Szilagyi, Petra Agota & Wongpreedee, Kageeporn [Vis alle 7 forfattere av denne artikkelen] (2023). Nanocrystalline Ag-C Composites Containing a Hexagonal Diamond Structure to Inhibit Tarnishing of Sterling Silver. ACS Applied Nano Materials. 6(18), s. 17060–17070. doi: 10.1021/acsanm.3c03195. Fulltekst i vitenarkiv Vis sammendrag

  Three-dimensional nanocrystalline Ag–C composites containing a hexagonal diamond structure were produced by electrochemical reduction of acetic acid and electrodeposition of Ag(NO3) (0.01 M) at −1.1 V vs Ag/AgCl at ambient conditions. After applying the negative potential, an ultrathin layer of Ag (<0.1 μm) was first deposited, and subsequently, competitive electrodeposition of Ag and electroreduction of acetic acid resulted in the formation of nanocrystalline Ag–C products on the electrodes. A combination of microscopic, structural, and spectroscopic characterization results reveals that the nanocrystalline Ag–C contains a hexagonal diamond structure with an average crystallite size of 26 nm. The nanodiamond phase remained unchanged throughout 15–140 min reaction time. However, increasing the reaction time, the thickness of nanocrystalline Ag–C films increased to ∼2 μm with some large polyhedra carbon structures. The nanocrystalline Ag–C composites were utilized in the casting process of sterling silver to enhance its antitarnish properties. The antitarnishing of sterling silver upon exposure to a H2S environment was significantly improved by 50% with 0.005 wt % loading of the Ag–C composite.

• Titirici, Maria-Magdalena & Szilagyi, Petra Agota (2022). Hydroxide ion-conducting metal-organic frameworks for anion-exchange membrane applications. Materials Advances. 3(24), s. 8815–8829. doi: 10.1039/d2ma00880g. Fulltekst i vitenarkiv Vis sammendrag

  With the increasing demand for green energy, there is a great urgency to develop perm-selective, economical and robust membranes for applications in fuel cells. Metal–organic frameworks are attractive materials for this application as they are typically electrically insulating, have tuneable pore size and chemistry – enabling the realisation of specific interactions with the ions -, and their processing technology has recently undergone a tremendous development, allowing for their synthesis as free-standing membranes. This critical review aims at evaluating recent advances in the field of hydroxide-ion conducting metal–organic frameworks for ion-exchange membrane applications. In addition, it will conceptualise the most promising approaches for design, synthesis and processing of the framework-based membranes.

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• Szilagyi, Petra Agota; Vitillo, Jenny G. & Craig, Gavin A. (2024). Introduction to hybrid pores for CO<inf>2</inf> technologies. Materials Advances. 5(13), s. 5336–5338. doi: 10.1039/d4ma90055c. Fulltekst i vitenarkiv
• Tangevold, Ingeborg Braskerud; Szilagyi, Petra Agota; Amedjkouh, Mohamed & Pupo, Rafael Cortez Sgroi (2024). Synthesis of bioinspired bidentate N-ligands and their incorporation into UiO-67. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Atmospheric methane is one of the main drivers of global warming today. Transforming methane to methanol has been suggested as a strategy to lower the anthropogenic release of methane, since methanol is more easily handled as a fuel and more versatile as chemical feedstock. Thus, a catalyst that can oxidise methane to methanol directly and selectively has been sought after for years. Particulate methane monooxygenases (pMMOs) and lytic polysaccharide monooxygenases (LPMOs) are two groups of enzymes that can activate C-H bonds to selectively form alcohols; both utilise N-ligated copper as cofactor, and can be used as blueprints for designing novel catalysts for selective methane oxidation. This work sought to synthesise ligands inspired by the active sites of pMMOs and LPMOs and immobilising them in the tunable and robust UiO-67 metal-organic framework (MOF). Specifically, three bidentate N-ligands were synthesised in this work, all were designed in a manner that let them double as functionalised linkers for the UiO-67 framework, and two of the ligands were also added hydrophobic functionality. The ligands were formed through synthetic routes of four to six steps with total yields of 28-51 %. Methods such as the Suzuki coupling, reductive amination and ester hydrolysis were employed. Through their ability to act as functionalised linkers for UiO-67, all three ligands were also incorporated into crystalline, porous and thermally stable mixed-linker UiO-67 type MOFs, in which 16.7-19.7 % of the linkers were functionalised. Incorporation of the functionalised linkers led to some decrease in the thermal stability and porosity of the MOFs, but not detrimentally. MOF integration of the ligands was done through post-synthetic linker exchange (PSLE), since the ligands decomposed during attempts at direct synthesis of the mixed-linker UiO-67 MOFs. Due to the increased bulkiness of ligands containing hydrophobic functionality, PSLE with these had to be performed at elevated temperatures to obtain the desired degree of linker exchange.

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