Kristoffer William Bø Hunvik

• Hunvik, Kristoffer William Bø; Seljelid, Konstanse Kvalem; Wallacher, Dirk; Kirch, Alexsandro; Cavalcanti, Leide Passos & Loch, Patrick [Vis alle 13 forfattere av denne artikkelen] (2023). Intercalation of CO2 Selected by Type of Interlayer Cation in Dried Synthetic Hectorite. Langmuir. ISSN 0743-7463. 39(14), s. 4895–4903. doi: 10.1021/acs.langmuir.2c03093. Fulltekst i vitenarkiv Vis sammendrag

  Clay minerals are abundant in caprock formations for anthropogenic storage sites for CO2, and they are potential capture materials for CO2 postcombustion sequestration. We investigate the response to CO2 exposure of dried fluorohectorite clay intercalated with Li+, Na+, Cs+, Ca2+, and Ba2+. By in situ powder X-ray diffraction, we demonstrate that fluorohectorite with Na+, Cs+, Ca2+, or Ba2+ does not swell in response to CO2 and that Li-fluorohectorite does swell. A linear uptake response is observed for Li-fluorohectorite by gravimetric adsorption, and we relate the adsorption to tightly bound residual water, which exposes adsorption sites within the interlayer. The experimental results are supported by DFT calculations.

• Hunvik, Kristoffer William Bø; Lima, Rodrigo José Da Silva; Kirch, Alexsandro; Loch, Patrick; Røren, Paul Monceyron & Petersen, Martin Hoffmann [Vis alle 13 forfattere av denne artikkelen] (2022). Influence of CO2 on Nanoconfined Water in a Clay Mineral. Journal of Physical Chemistry C. ISSN 1932-7447. 126(40), s. 17243–17254. doi: 10.1021/acs.jpcc.2c03310. Fulltekst i vitenarkiv Vis sammendrag

  Developing new technologies for carbon sequestration and long-term carbon storage is important. Clay minerals are interesting in this context as they are low-cost, naturally abundant, can adsorb considerable amounts of CO2, and are present in storage sites for anthropogenic carbon. Here, to better understand the intercalation mechanisms of CO2 in dehydrated and hydrated synthetic Na-fluorohectorite clay, we have combined powder X-ray diffraction, inelastic and quasi-elastic neutron scattering, and density functional theory calculations. For dehydrated Na-fluorohectorite, we observe no crystalline swelling or spectroscopic changes in response to CO2, whereas for the hydrated case, damping of the librational modes related to the intercalated water was clearly observed. These findings suggest the formation of a more disordered water coordination in the interlayer associated with highly confined water molecules. From the simulations, we conclude that intercalated water molecules decrease the layer–layer cohesion energy and create physical space for CO2 intercalation. Furthermore, we confirm that interlayer confinement reduces the Na+ hydration number when compared to that in bulk aqueous water, which may allow for proton transfer and hydroxide formation followed by CO2 adsorption in the form of carbonates. The experimental results are discussed in the context of previous and present observations on, a similar smectite, Ni-fluorohectorite, for which it is established that CO2 attaches to the edge of nickel hydroxide islands present in the interlayer.

• Røren, Paul Monceyron; Hunvik, Kristoffer William Bø; Josvanger, Vegard; Buset, Ole Tore & Fossum, Jon Otto (2021). Controlled Sample Environment for Studying Solid-Gas Interactions by in situ Powder X-ray Diffraction. Journal of Applied Crystallography. ISSN 0021-8898. 54, s. 371–375. doi: 10.1107/S1600576720014776. Fulltekst i vitenarkiv
• Brito, Paulo Henrique Michels; Miranda, Leander Edward Michels Brito; Hunvik, Kristoffer William Bø; Santos, Everton; Pacáková, Barbara & Cavalcanti, Leide Passos [Vis alle 9 forfattere av denne artikkelen] (2021). Experimental methods to study clay minerals and perspective applications of Fluorohectorite. Materials and devices. ISSN 2495-3911. s. 601–601. doi: 10.23647/ca.md20201501. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Loch, Patrick; Wallacher, Dirk; Kirch, Alexsandro; Cavalcanti, Leide Passos & Rieß, Martin [Vis alle 14 forfattere av denne artikkelen] (2021). CO2 Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral. Langmuir. ISSN 0743-7463. 37(49), s. 14491–14499. doi: 10.1021/acs.langmuir.1c02467. Fulltekst i vitenarkiv Vis sammendrag

  Due to the compact two-dimensional interlayer pore space and the high density of interlayer molecular adsorption sites, clay minerals are competitive adsorption materials for carbon dioxide capture. We demonstrate that with a decreasing interlayer surface charge in a clay mineral, the adsorption capacity for CO2 increases, while the pressure threshold for adsorption and swelling in response to CO2 decreases. Synthetic nickel-exchanged fluorohectorite was investigated with three different layer charges varying from 0.3 to 0.7 per formula unit of Si4O10F2. We associate the mechanism for the higher CO2 adsorption with more accessible space and adsorption sites for CO2 within the interlayers. The low onset pressure for the lower-charge clay is attributed to weaker cohesion due to the attractive electrostatic forces between the layers. The excess adsorption capacity of the clay is measured to be 8.6, 6.5, and 4.5 wt % for the lowest, intermediate, and highest layer charges, respectively. Upon release of CO2, the highest-layer charge clay retains significantly more CO2. This pressure hysteresis is related to the same cohesion mechanism, where CO2 is first released from the edges of the particles thereby closing exit paths and trapping the molecules in the center of the clay particles.

• Raaen, Steinar & Hunvik, Kristoffer William Bø (2020). Non-activated adsorption of methane on nickel surfaces induced by reduced work function. Applied Surface Science. ISSN 0169-4332. 528. doi: 10.1016/j.apsusc.2020.146955. Fulltekst i vitenarkiv Vis sammendrag

  Adsorption of methane has been studied in ultrahigh vacuum environments on single crystalline as well as on Ni nano-particles on mica substrates. Experimental techniques have been X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) and temperature programmed desorption spectroscopy (TPD). In accordance with previous observations only physisorption of is observed on pure nickel at temperatures below 130 K for exposures in the high vacuum regime. TPD in the temperature range from 200 to 300 K shows that chemisorption of methane takes place when the sample work function is lowered by about 0.7 eV by a surface treatment, which presumably exposes the surface to atomic hydrogen. The lowered work function enables charge transfer from the Ni conduction band to the methane affinity level which subsequent leads to dissociative chemisorption.

• Miranda, Leander Edward Michels Brito; Fonesca, C. L. S. da; Méheust, Y.; Altoé, M. A. S.; Santos, E. C. dos & Grassi, G. [Vis alle 13 forfattere av denne artikkelen] (2020). The Impact of Thermal History on Water Adsorption in a Synthetic Nanolayered Silicate with Intercalated Li+ or Na+. Journal of Physical Chemistry C. ISSN 1932-7447. 124(45), s. 24690–24703. doi: 10.1021/acs.jpcc.0c05847. Fulltekst i vitenarkiv Vis sammendrag

  For applications benefitting from the swelling properties of nanolayered silicates (clay minerals), it is of paramount importance to understand the hysteresis in the clay–water interaction. In this context, the present work investigates how the thermal history of Na+- and Li+-intercalated fluorohectorite affects the hydration process. By combining X-ray diffraction and thermogravimetric analysis, water adsorption of preheated and non-preheated fluorohectorite was measured and analyzed in terms of the characteristic interlayer distance. The number of water molecules per cation was also inferred. We find that some of the hydration states in preheated samples are suppressed, and transitions to higher hydration states are achieved at higher relative humidity values. This could be due to the initial water content that facilities crystalline swelling. However, the data for Li-fluorohectorite do not exclude the possibility of a low temperature Hofmann–Klemen effect at 150 °C. Our study also provides strong hints that the so-called 1.5 water layer state, observed in previous studies on smectites, is a metastable state. In addition, the impact of a hydrogenous structure in the interlayer space of Li-fluorohectorite on the clay’s hydration behavior is demonstrated. The results, if generalized, would have strong implications on a wide range of applications, where the thermal history of smectites is important.

• Hunvik, Kristoffer William Bø; Pacáková, Barbara & Raaen, Steinar (2020). CO2 adsorption on pure and oxidised Ni nano-structures deposited on mica surfaces. Philosophical Magazine. ISSN 1478-6435. 101, s. 387–399. doi: 10.1080/14786435.2020.1838654. Fulltekst i vitenarkiv Vis sammendrag

  Adsorption and desorption of CO2 on metallic and oxidised Ni nano-structures supported on mica (muscovite) substrates have been studied by temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Predominantly physisorption was observed at low temperatures near 130 K. Weak desorption features were found at temperatures up to about room temperature for both metallic and oxidised samples. No clear indication of dissociation of CO2 was found on neither the oxidised nor the metallic sample. More CO2 was observed to adsorb on oxidised Ni nano-structures as compared to the metallic structures. A large affinity to adsorption of CO from the ambient vacuum was seen on the nano-structures. An absence of strong dependence on Ni amount on CO2 adsorption is reported.

• Loch, Patrick; Hunvik, Kristoffer William Bø; Puchtler, Florian; Weiss, Sebastian; Seljelid, Konstanse Kvalem & Røren, Paul Monceyron [Vis alle 12 forfattere av denne artikkelen] (2020). Spontaneous formation of an ordered interstratification upon Ni-exchange of Na-fluorohectorite. Applied Clay Science. ISSN 0169-1317. 198. doi: 10.1016/j.clay.2020.105831. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Loch, Patrick; Cavalcanti, Leide Passos; Seljelid, Konstanse Kvalem; Røren, Paul Monceyron & Rudic, Svemir [Vis alle 13 forfattere av denne artikkelen] (2020). CO2 Capture by Nickel Hydroxide Interstratified in the Nanolayered Space of a Synthetic Clay Mineral. Journal of Physical Chemistry C. ISSN 1932-7447. 124(48), s. 26222–26231. doi: 10.1021/acs.jpcc.0c07206. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Støvneng, Anna; Pacáková, Barbara & Raaen, Steinar (2019). CO desorption from nickel-decorated muscovite mica. Applied Surface Science. ISSN 0169-4332. 490, s. 430–435. doi: 10.1016/j.apsusc.2019.06.073. Fulltekst i vitenarkiv Vis sammendrag

  Adsorption and desorption of CO from Ni nanostructures deposited on muscovite mica substrates have been studied by TPD and characterized by XPS and AFM. In agreement with previous reports it is found that CO does not adsorb on the bare mica substrate. The desorption spectra depend strongly on the Ni coverage on the mica substrate. Three coverage regimes have been found; for low Ni coverage of approximately 0.2 monolayers a dominant desorption peak is found near 400 K. For medium coverage of approximately 0.6 monolayers three distinct peaks appear in the temperature region from 250 to 550 K. For higher Ni coverage of approximately 3 monolayers a single peak is observed near 550 K. The high temperature peak was assigned to desorption from terrace sites, the medium temperature peak was assigned to step sites, and the low temperature peak was argued to stem from lateral interaction between adsorbed CO species and possible sites with low coordination, e.g. kink sites. Desorption parameters have been extracted from the low temperature part of the desorption spectra. Anomalous low values for the vibrational prefactors were obtained in the case of low Ni coverage. This is argued to be due to dissociation of CO.

• Bawden, L; Cooil, Simon Phillip; Mazzola, Federico; Riley, JM; Collins-Mcintyre, LJ & Sunko, V [Vis alle 16 forfattere av denne artikkelen] (2016). Spin-valley locking in the normal state of a transition-metal dichalcogenide superconductor. Nature Communications. 7. doi: 10.1038/ncomms11711. Fulltekst i vitenarkiv Vis sammendrag

  Metallic transition-metal dichalcogenides (TMDCs) are benchmark systems for studying and controlling intertwined electronic orders in solids, with superconductivity developing from a charge-density wave state. The interplay between such phases is thought to play a critical role in the unconventional superconductivity of cuprates, Fe-based and heavy-fermion systems, yet even for the more moderately-correlated TMDCs, their nature and origins have proved controversial. Here, we study a prototypical example, 2H-NbSe2, by spin- and angle-resolved photoemission and first-principles theory. We find that the normal state, from which its hallmark collective phases emerge, is characterized by quasiparticles whose spin is locked to their valley pseudospin. This results from a combination of strong spin–orbit interactions and local inversion symmetry breaking, while interlayer coupling further drives a rich three-dimensional momentum dependence of the underlying Fermi-surface spin texture. These findings necessitate a re-investigation of the nature of charge order and superconducting pairing in NbSe2 and related TMDCs.

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• Seljelid, Konstanse Kvalem; Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos; Riess, Martin; Loch, Patrick & Josvanger, Vegard [Vis alle 13 forfattere av denne artikkelen] (2022). CO2 intercalation in clay minerals. Fulltekst i vitenarkiv
• Miranda, Leander Edward Michels Brito; Santos, Everton; Pacáková, Barbara; Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos & Araki, Koiti [Vis alle 9 forfattere av denne artikkelen] (2019). In‐situ intercalation of pharmaceutics in smectite clays. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos; Michels-Brito, Paulo; Daab, Mathias; Seljelid, Konstanse Kvalem & Josvanger, Vegard [Vis alle 11 forfattere av denne artikkelen] (2019). Determining the role of the ionic radii of interlayer cations for CO2 capture in smectite clay. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos; Riess, Martin; Loch, Patrick; Seljelid, Konstanse Kvalem & Josvanger, Vegard [Vis alle 13 forfattere av denne artikkelen] (2019). The Role of Interlayer Cations for CO2 Capture in a Smectite Clay. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos; Riess, Martin; Loch, Patrick; Seljelid, Konstanse Kvalem & Josvanger, Vegard [Vis alle 13 forfattere av denne artikkelen] (2019). Carbon dioxide and methane selectivity of a smectite clay with different intercalated cations. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos; Daab, Mathias; Pacáková, Barbara; Brito, Paulo Henrique Michels & Knudsen, Kenneth Dahl [Vis alle 8 forfattere av denne artikkelen] (2018). Determining the Role of the Ionic Radii of Interlayer Cations for CO2 Capture in Synthetic Smectite Clay. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William; Støvneng, Anna; Pacáková, Barbara & Raaen, Steinar (2018). Adsorption of CO on Nickel-decorated Muscovite Mica. Fulltekst i vitenarkiv
• Brito, Paulo Michels; Pachakova, Barbara; Godrich, Sebastian; Hunvik, Kristoffer William Bø; Breu, Joseph & Fossum, Jon Otto (2018). "Nanolayered Clay—2D Natural Material" B. Pacakova, P.H. Michels Brito, S. Godrich, K.W.B. Hunvik1, J. Breu, J. O. Fossum, Poster session at MAX IV Summer School, May 21-29 2018. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Cavalcanti, Leide Passos; Daab, Mathias; Michels-Brito, Paulo; Pacáková, Barbara & Knudsen, Kenneth Dahl [Vis alle 8 forfattere av denne artikkelen] (2018). Determining the role of the ionic radii of interlayer cations for CO2 capture in smectite clay. Fulltekst i vitenarkiv
• Pacáková, Barbara; Godrich, Sebastian; Hunvik, Kristoffer William; Breu, Joseph & Fossum, Jon Otto (2017). Nanolayered Clay — a 2D Natural Material. Fulltekst i vitenarkiv Vis sammendrag

  Layered materials1 are in the centre of interest since the discovery of graphene. One of the methods used for producing thin, 2-dimensional (2D) sheets from those materials is liquid exfoliation2, which enables production of thin layers and layered metamaterial composites. Many layered compounds can be exfoliated using ion intercalation, often resulting in structural deformation, thus sonication in organic solvents has become very much used2,3. However; efficient exfoliation by exposure of a layered material to ultrasonic waves usually requires use of long sonication times and relatively high power4, which together with the toxicity of the organic solvents make the method environmentally unfriendly and this triggers interests for procedures adopted for aqueous solutions3. Here we present an example of a layered material which naturally exfoliates after immersion into water, namely nanolayered clay5,6, which generally does not require any of the procedures described above. We discuss swelling and exfoliation potential7 of several types of clay (hectorite, laponite, natural vermiculite) and the quality of exfoliated 2D sheets that can be obtained. Perspectives for inclusion of 2D clays in Van der Waals heterostructure devices is discussed. References: 1. Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2014). 2. Nicolosi, V. et al. Liquid Exfoliation of Layered Materials. Science 340, (2013). 3. Smith, R. J. et al. Large-scale exfoliation of inorganic layered compounds in aqueous surfactant solutions. Adv. Mater. 23, 3944–3948 (2011). 4. Kouroupis-Agalou, K. et al. Fragmentation and exfoliation of 2-dimensional materials: a statistical approach. Nanoscale 6, 5926–33 (2014). 5. Mukherjee, S. Classification and Composition of Clay Constituents. The Science of Clays: Applications in Industry, Engineering and Environment (Springer Netherlands, 2013). doi:10.1007/978-94-007-6683-9_2 6. E. L. Hansen, H. Hemmen, D. M. Fonseca, C. Coutant, K. D. Knudsen, T. S. Plivelic, D. Bonn & J. O. Fossum, Swelling transition of a clay induced by heating. Scientific Reports 2, 618 (2012). 7. Rosenfeldt, S. et al. In-Depth Insights into the Key Steps of Delamination of Charged 2D Nanomaterials. Langmuir 32, 10582–10588 (2016).

• Hunvik, Kristoffer William; Yu, Xiaofeng; Raaen, Steinar & Fossum, Jon Otto (2017). Absorption and desorption of CO2 in vermiculite and fluorohectorite clays as studied by photoemission and temperature programmed desorption. Fulltekst i vitenarkiv
• Hetland, Øyvind Storesund; Kjellstadli, Jonas Tøgersen; Hunvik, Kristoffer William & McDougall, Siv-Marie (2016). Heit? - Varmemagi i Praksis: Stand på vegne av Insitutt for Fysikk med Peltierelement for demonstrasjon av termisk fysikk. Fulltekst i vitenarkiv
• Hunvik, Kristoffer William Bø; Raaen, Steinar; Fossum, Jon Otto & Knudsen, Kenneth Dahl (2020). Physicochemical mechanisms for gas adsorption on clay mineral interfaces and surfaces. Norges teknisk-naturvitenskapelige universitet. ISSN 9788232649815. Fulltekst i vitenarkiv Vis sammendrag

  Increasing anthropogenic carbon emissions have a detrimental impact on our planet's ecosystems. If we want to keep our planet habitable for future generations, serious action is needed. We need to both reduce and mitigate our carbon emissions through utilization or storage. In this context, clay minerals are interesting. They are naturally abundant, provide large surface areas, are stable, have a low cost and are present in caprock formations for geological storage of carbon. Clay minerals are layered materials where the electrostatic forces hold together stacks of phyllosilicate layers. In this thesis, the adsorption of carbonaceous gases are investigated on pure and nano-functionalized clay mineral surfaces and interfaces to provide deeper insight into relevant physicochemical processes. By employing a surface science approach, adsorption of CO, CO2 and CH4 by nickel nanostructures on muscovite mica are studied with photoemission spectroscopy, temperature-programmed desorption and atomic force microscopy. The thesis investigates how coverage and size of the nanostructures affects the adsorption of CO, how oxidation of the nanostructures increases the CO2 adsorption and how atomic hydrogen presumably results in the chemisorption of CH4 on Ni surfaces. From a bulk and interface perspective, with X-ray and neutron diffraction, inelastic neutron spectroscopy, Raman spectroscopy and gravimetric adsorption, it is found that swelling and adsorption of CO2 in fluorohectorite is heavily dependent on the interlayer species. No adsorption of CO2 for dehydrated fluorohectorite with Na+, Cs+, Ca2+ and Ba2+ as the interlayer cations was observed, in partial disagreement with published literature. However, when fluorohectorite was exchanged for Li+ or Ni2+ swelling and uptake was observed in response to CO2. The thesis investigates the underlying mechanisms, showing a previously overlooked ordered interstratification of a nickel hydroxide species, how this species relates to CO2 adsorption, how the capacity for CO2 may be tuned by controlling the layer charge of each platelet and trying unravel how water present in the clay may affect the adsorption properties. The results demonstrate new pathways for controlling the adsorption of carbonaceous gases in clay minerals, which ultimately may increase their technological relevance as gas adsorption materials.

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