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Holm, A., Davies, B., Boscolo Bibi, S., Moncada, F., Halldin-Stenlid, J., Paškevičius, L., . . . Koroidov, S. (2024). A Water-Promoted Mars-van Krevelen Reaction Dominates Low-Temperature CO Oxidation over Au-Fe2O3 but Not over Au-TiO2. ACS Catalysis, 14(5), 3191-3197
Åpne denne publikasjonen i ny fane eller vindu >>A Water-Promoted Mars-van Krevelen Reaction Dominates Low-Temperature CO Oxidation over Au-Fe2O3 but Not over Au-TiO2
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2024 (engelsk)Inngår i: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 14, nr 5, s. 3191-3197Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We provide experimental evidence that is inconsistent with often proposed Langmuir−Hinshelwood (LH) mechanistic hypotheses for water-promoted CO oxidation over Au–Fe2O3. Passing CO and H2O, but no O2, over Au-γ-Fe2O3 at 25 °C, we observe significant CO2 production, inconsistent with LH mechanistic hypotheses. Experiments with H218O further show that previous LH mechanistic proposals cannot account for water-promoted CO oxidation over Au-γ-Fe2O3. Guided by density functional theory, we instead postulate a water-promoted Mars–van Krevelen (w-MvK) reaction. Our proposed w-MvK mechanism is consistent both with observed CO2 production in the absence of O2 and with CO oxidation in the presence of H218O and 16O2. In contrast, for Au-TiO2, our data is consistent with previous LH mechanistic hypotheses. 

Emneord
CO oxidation, Mars−van Krevelen, Langmuir−Hinshelwood, mechanism, Au Fe2O3, TiO2
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-227301 (URN)10.1021/acscatal.3c05978 (DOI)001166445100001 ()38449533 (PubMedID)2-s2.0-85185599124 (Scopus ID)
Tilgjengelig fra: 2024-03-19 Laget: 2024-03-19 Sist oppdatert: 2024-03-19bibliografisk kontrollert
Durr, R. N., Maltoni, P., Feng, S., Ghorai, S., Strom, P., Tai, C.-W., . . . Edvinsson, T. (2024). Clearing Up Discrepancies in 2D and 3D Nickel Molybdate Hydrate Structures. Inorganic Chemistry, 63(5), 2388-2400
Åpne denne publikasjonen i ny fane eller vindu >>Clearing Up Discrepancies in 2D and 3D Nickel Molybdate Hydrate Structures
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2024 (engelsk)Inngår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 63, nr 5, s. 2388-2400Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

When electrocatalysts are prepared, modification of the morphology is a common strategy to enhance their electrocatalytic performance. In this work, we have examined and characterized nanorods (3D) and nanosheets (2D) of nickel molybdate hydrates, which previously have been treated as the same material with just a variation in morphology. We thoroughly investigated the materials and report that they contain fundamentally different compounds with different crystal structures, chemical compositions, and chemical stabilities. The 3D nanorod structure exhibits the chemical formula NiMoO4<middle dot>0.6H(2)O and crystallizes in a triclinic system, whereas the 2D nanosheet structures can be rationalized with Ni3MoO5-0.5x(OH)(x)<middle dot>(2.3 - 0.5x)H2O, with a mixed valence of both Ni and Mo, which enables a layered crystal structure. The difference in structure and composition is supported by X-ray photoelectron spectroscopy, ion beam analysis, thermogravimetric analysis, X-ray diffraction, electron diffraction, infrared spectroscopy, Raman spectroscopy, and magnetic measurements. The previously proposed crystal structure for the nickel molybdate hydrate nanorods from the literature needs to be reconsidered and is here refined by ab initio molecular dynamics on a quantum mechanical level using density functional theory calculations to reproduce the experimental findings. Because the material is frequently studied as an electrocatalyst or catalyst precursor and both structures can appear in the same synthesis, a clear distinction between the two compounds is necessary to assess the underlying structure-to-function relationship and targeted electrocatalytic properties.

HSV kategori
Identifikatorer
urn:nbn:se:su:diva-226960 (URN)10.1021/acs.inorgchem.3c03261 (DOI)001158182800001 ()38242537 (PubMedID)
Tilgjengelig fra: 2024-02-29 Laget: 2024-02-29 Sist oppdatert: 2024-02-29bibliografisk kontrollert
Ali, H., Rusz, J., Bürgler, D. E., Adam, R., Schneider, C. M., Tai, C.-W. & Thersleff, T. (2024). Noise-dependent bias in quantitative STEM-EMCD experiments revealed by bootstrapping. Ultramicroscopy, 257, Article ID 113891.
Åpne denne publikasjonen i ny fane eller vindu >>Noise-dependent bias in quantitative STEM-EMCD experiments revealed by bootstrapping
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2024 (engelsk)Inngår i: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 257, artikkel-id 113891Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Electron magnetic circular dichroism (EMCD) is a powerful technique for estimating element-specific magnetic moments of materials on nanoscale with the potential to reach atomic resolution in transmission electron microscopes. However, the fundamentally weak EMCD signal strength complicates quantification of magnetic moments, as this requires very high precision, especially in the denominator of the sum rules. Here, we employ a statistical resampling technique known as bootstrapping to an experimental EMCD dataset to produce an empirical estimate of the noise-dependent error distribution resulting from application of EMCD sum rules to bcc iron in a 3-beam orientation. We observe clear experimental evidence that noisy EMCD signals preferentially bias the estimation of magnetic moments, further supporting this with error distributions produced by Monte-Carlo simulations. Finally, we propose guidelines for the recognition and minimization of this bias in the estimation of magnetic moments.

Emneord
Electron magnetic circular dichroism, Electron energy loss spectroscopy, Scanning, Transmission electron microscopy, Bootstrapping, Noise dependent bias, Error analysis
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-225757 (URN)10.1016/j.ultramic.2023.113891 (DOI)001132754500001 ()38043363 (PubMedID)2-s2.0-85178597506 (Scopus ID)
Tilgjengelig fra: 2024-01-23 Laget: 2024-01-23 Sist oppdatert: 2024-01-30bibliografisk kontrollert
Mikheenkova, A., Mukherjee, S., Hirsbrunner, M., Törnblom, P., Tai, C.-W., Segre, C. U., . . . Hahlin, M. (2024). The role of oxygen in automotive grade lithium-ion battery cathodes: an atomistic survey of ageing. Journal of Materials Chemistry A, 12(4), 2465-2478
Åpne denne publikasjonen i ny fane eller vindu >>The role of oxygen in automotive grade lithium-ion battery cathodes: an atomistic survey of ageing
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2024 (engelsk)Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 12, nr 4, s. 2465-2478Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The rising demand for high-performance lithium-ion batteries, pivotal to electric transportation, hinges on key materials like the Ni-rich layered oxide LiNixCoyAlzO2 (NCA) used in cathodes. The present study investigates the redox mechanisms, with particular focus on the role of oxygen in commercial NCA electrodes, both fresh and aged under various conditions (aged cells have performed >900 cycles until a cathode capacity retention of ∼80%). Our findings reveal that oxygen participates in charge compensation during NCA delithiation, both through changes in transition metal (TM)–O bond hybridization and formation of partially reversible O2, the latter occurs already below 3.8 V vs. Li/Li+. Aged NCA material undergoes more significant changes in TM–O bond hybridization when cycling above 50% SoC, while reversible O2 formation is maintained. Nickel is found to be redox active throughout the entire delithiation and shows a more classical oxidation state change during cycling with smaller changes in the Ni–O hybridization. By contrast, Co redox activity relies on a stronger change in Co–O hybridization, with only smaller Co oxidation state changes. The Ni–O bond displays an almost twice as large change in its bond length on cycling as the Co–O bond. The Ni–O6 octahedra are similar in size to the Co–O6 octahedra in the delithiated state, but are larger in the lithiated state, a size difference that increases with battery ageing. These contrasting redox activities are reflected directly in structural changes. The NCA material exhibits the formation of nanopores upon ageing, and a possible connection to oxygen redox activity is discussed. The difference in interaction of Ni and Co with oxygen provides a key understanding of the mechanism and the electrochemical instability of Ni-rich layered transition metal oxide electrodes. Our research specifically highlights the significance of the role of oxygen in the electrochemical performance of electric-vehicle-grade NCA electrodes, offering important insights for the creation of next-generation long-lived lithium-ion batteries.

HSV kategori
Identifikatorer
urn:nbn:se:su:diva-226137 (URN)10.1039/d3ta05516g (DOI)001135752700001 ()38269086 (PubMedID)2-s2.0-85182225074 (Scopus ID)
Tilgjengelig fra: 2024-02-01 Laget: 2024-02-01 Sist oppdatert: 2024-02-01bibliografisk kontrollert
Rafi, A. A., Alimohammadzadeh, R., Avella, A., Mõistlik, T., Jűrisoo, M., Kaaver, A., . . . Cordova, A. (2023). A facile route for concurrent fabrication and surface selective functionalization of cellulose nanofibers by lactic acid mediated catalysis. Scientific Reports, 13, Article ID 14730.
Åpne denne publikasjonen i ny fane eller vindu >>A facile route for concurrent fabrication and surface selective functionalization of cellulose nanofibers by lactic acid mediated catalysis
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2023 (engelsk)Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 13, artikkel-id 14730Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Celulose nanofibers are lightweight, recycable, biodegradable, and renewable. Hence, there is a great interest of using them instead of fossil-based components in new materials and biocomposites. In this study, we disclose an environmentally benign (green) one-step reaction approach to fabricate lactic acid ester functionalized cellulose nanofibrils from wood-derived pulp fibers in high yields. This was accomplished by converting wood-derived pulp fibers to nanofibrillated “cellulose lactate” under mild conditions using lactic acid as both the reaction media and catalyst. Thus, in parallel to the cellulose nanofibril production, concurrent lactic acid-catalyzed esterification of lactic acid to the cellulose nanofibers surface occured. The direct lactic acid esterification, which is a surface selective functionalization and reversible (de-attaching the ester groups by cleavage of the ester bonds), of the cellulose nanofibrils was confirmed by low numbers of degree of substitution, and FT-IR analyses. Thus, autocatalytic esterification and cellulose hydrolysis occurred without the need of metal based or a harsh mineral acid catalysts, which has disadvantages such as acid corrosiveness and high recovery cost of acid. Moreover, adding a mineral acid as a co-catalyst significantly decreased the yield of the nanocellulose. The lactic acid media is successfully recycled in multiple reaction cycles producing the corresponding nanocellulose fibers in high yields. The disclosed green cellulose nanofibril production route is industrial relevant and gives direct access to nanocellulose for use in variety of applications such as sustainable filaments, composites, packaging and strengthening of recycled fibers.

HSV kategori
Identifikatorer
urn:nbn:se:su:diva-226642 (URN)10.1038/s41598-023-41989-3 (DOI)001142021200013 ()37679445 (PubMedID)2-s2.0-85170181889 (Scopus ID)
Tilgjengelig fra: 2024-02-15 Laget: 2024-02-15 Sist oppdatert: 2024-02-15bibliografisk kontrollert
Li, S., Chai, Z., Wang, Z., Tai, C.-W., Zhu, J., Edström, K. & Ma, Y. (2023). A Multiscale, Dynamic Elucidation of Li Solubility in the Alloy and Metallic Plating Process. Advanced Materials, 35(47), Article ID 2306826.
Åpne denne publikasjonen i ny fane eller vindu >>A Multiscale, Dynamic Elucidation of Li Solubility in the Alloy and Metallic Plating Process
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2023 (engelsk)Inngår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 35, nr 47, artikkel-id 2306826Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Li-containing alloys and metallic deposits offer substantial Li+ storage capacities as alternative anodes to commercial graphite. However, the thermodynamically in sequence, yet kinetically competitive mechanism between Li solubility in the solid solution and intermediate alloy-induced Li deposition remains debated, particularly across the multiple scales. The elucidation of the mechanism is rather challenging due to the dynamic alloy evolution upon the non-equilibrium, transient lithiation processes under coupled physical fields. Here, influential factors governing Li solubility in the Li-Zn alloy are comprehensively investigated as a demonstrative model, spanning from the bulk electrolyte solution to the ion diffusion within the electrode. Through real-time phase tracking and spatial distribution analysis of intermediate alloy/Li metallic species at varied temperatures, current densities and particle sizes, the driving force of Li solubility and metallic plating along the Li migration pathway are probed in-depth. This study investigates the correlation between kinetics (pronounced concentration polarization, miscibility gap in lattice grains) and rate-limiting interfacial charge transfer thermodynamics in dedicating the Li diffusion into the solid solution. Additionally, the lithiophilic alloy sites with the balanced diffusion barrier and Li adsorption energy are explored to favor the homogeneous metal plating, which provides new insights for the rational innovation of high-capacity alloy/metallic anodes.

Emneord
decoupled physical fields, dynamic phasic change, lithiophilic alloys, multiscale Li+ migration pathways, operando characterization
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-223749 (URN)10.1002/adma.202306826 (DOI)001084858600001 ()37769145 (PubMedID)2-s2.0-85174214723 (Scopus ID)
Tilgjengelig fra: 2023-11-17 Laget: 2023-11-17 Sist oppdatert: 2024-01-11bibliografisk kontrollert
Saadattalab, V., Wu, J., Tai, C.-W., Bacsik, Z. & Hedin, N. (2023). Adsorption of volatile organic compounds on activated carbon with included iron phosphate. Carbon trends, 11, Article ID 100259.
Åpne denne publikasjonen i ny fane eller vindu >>Adsorption of volatile organic compounds on activated carbon with included iron phosphate
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2023 (engelsk)Inngår i: Carbon trends, ISSN 2667-0569, Vol. 11, artikkel-id 100259Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Volatile organic compounds (VOCs) are often hazardous and need commonly to be removed from gas mixtures. Capture on activated carbon (AC) is one approach to achieving this. We hypothesized that the smallest pores on ACs and the inclusion of inorganic phosphates could enhance the low gas pressure uptake of two typical VOCs (acetone and isopropanol). To test this hypothesis, ACs were prepared by chemical activation of hydrochars with H3PO4 or a mixture of FeCl3 and H3PO4. The hydrochars had been prepared by hydrothermal carbonization of glucose. The ACs were characterized by XRD, IR, TGA, and the adsorption of N2, CO2, H2O, acetone, and isopropanol. The results showed that the ACs had comparably high adsorption of acetone and isopropanol at low vapor pressures. The low-pressure uptake (at 0.03 kPa) of isopropanol and acetone had values of up to 3.4 mmol/g and 2.2 mmol/g, respectively. This suggests that ACs containing iron phosphate could be of relevance for adsorption driven removal of VOC. It was also observed that the external surface area of the ACs containing iron phosphates increased upon secondary heat treatment in N2.

HSV kategori
Identifikatorer
urn:nbn:se:su:diva-228544 (URN)10.1016/j.cartre.2023.100259 (DOI)001030948100001 ()2-s2.0-85151239392 (Scopus ID)
Forskningsfinansiär
Mistra - The Swedish Foundation for Strategic Environmental Research, 2015/31Knut and Alice Wallenberg Foundation
Tilgjengelig fra: 2024-04-22 Laget: 2024-04-22 Sist oppdatert: 2024-04-22bibliografisk kontrollert
Mikheenkova, A., Smith, A. J., Frenander, K. B., Tesfamhret, Y., Chowdhury, N. R., Tai, C.-W., . . . Lacey, M. J. (2023). Ageing of High Energy Density Automotive Li-Ion Batteries: The Effect of Temperature and State-of-Charge. Journal of the Electrochemical Society, 170(8), Article ID 080503.
Åpne denne publikasjonen i ny fane eller vindu >>Ageing of High Energy Density Automotive Li-Ion Batteries: The Effect of Temperature and State-of-Charge
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2023 (engelsk)Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 170, nr 8, artikkel-id 080503Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Lithium ion batteries (LIB) have become a cornerstone of the shift to electric transportation. In an attempt to decrease the production load and prolong battery life, understanding different degradation mechanisms in state-of-the-art LIBs is essential. Here, we analyze how operational temperature and state-of-charge (SoC) range in cycling influence the ageing of automotive grade 21700 batteries, extracted from a Tesla 3 long Range 2018 battery pack with positive electrode containing LiNi(x)CoyAl(z)O(2) (NCA) and negative electrode containing SiOx-C. In the given study we use a combination of electrochemical and material analysis to understand degradation sources in the cell. Herein we show that loss of lithium inventory is the main degradation mode in the cells, with loss of material on the negative electrode as there is a significant contributor when cycled in the low SoC range. Degradation of NCA dominates at elevated temperatures with combination of cycling to high SoC (beyond 50%). (c) 2023 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BYNC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: permissions@ioppublishing.org.

HSV kategori
Identifikatorer
urn:nbn:se:su:diva-221347 (URN)10.1149/1945-7111/aceb8f (DOI)001044526800001 ()2-s2.0-85167873770 (Scopus ID)
Tilgjengelig fra: 2023-09-25 Laget: 2023-09-25 Sist oppdatert: 2023-09-25bibliografisk kontrollert
Deiana, L., Rafi, A. A., Tai, C.-W., Bäckvall, J.-E. & Cordova, A. (2023). Artificial Arthropod Exoskeletons/Fungi Cell Walls Integrating Metal and Biocatalysts for Heterogeneous Synergistic Catalysis of Asymmetric Cascade Transformations. ChemCatChem, 15(15), Article ID e202300250.
Åpne denne publikasjonen i ny fane eller vindu >>Artificial Arthropod Exoskeletons/Fungi Cell Walls Integrating Metal and Biocatalysts for Heterogeneous Synergistic Catalysis of Asymmetric Cascade Transformations
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2023 (engelsk)Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 15, nr 15, artikkel-id e202300250Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

A novel and sustainable tandem-catalysis system for asymmetric synthesis is disclosed, which is fabricated by bio-inspired self-assembly of artificial arthropod exoskeletons (AAEs) or artificial fungi cell walls (AFCWs) containing two different types of catalysts (enzyme and metal nanoparticles). The heterogeneous integrated enzyme/metal nanoparticle AAE/AFCW systems, which contain chitosan as the main structural component, co-catalyze dynamic kinetic resolution of primary amines via a tandem racemization/enantioselective amidation reaction process to give the corresponding amides in high yields and excellent ee. The heterogeneous AAE/AFCW systems display successful heterogeneous synergistic catalysis at the surfaces since they can catalyze multiple reaction cycles without metal leaching. The use of natural-based and biocompatible structural components makes the AAE/AFCW systems fully biodegradable and renewable, thus fulfilling important green chemistry requirements. 

Emneord
asymmetric tandem catalysis, chiral amines, chitosan, dynamic kinetic resolution, heterogeneous hybrid catalyst
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-221309 (URN)10.1002/cctc.202300250 (DOI)001022816700001 ()2-s2.0-85164018579 (Scopus ID)
Tilgjengelig fra: 2023-09-19 Laget: 2023-09-19 Sist oppdatert: 2023-09-21bibliografisk kontrollert
Deiana, L., Badali, E., Rafi, A. A., Tai, C.-W., Bäckvall, J.-E. & Cordova, A. (2023). Cellulose-Supported Heterogeneous Gold-Catalyzed Cycloisomerization Reactions of Alkynoic Acids and Allenynamides. ACS Catalysis, 13(15), 10418-10424
Åpne denne publikasjonen i ny fane eller vindu >>Cellulose-Supported Heterogeneous Gold-Catalyzed Cycloisomerization Reactions of Alkynoic Acids and Allenynamides
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2023 (engelsk)Inngår i: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 13, nr 15, s. 10418-10424Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Herein, we describe efficient nanogold-catalyzed cycloisomerization reactions of alkynoic acids and allenynamides to enol lactones and dihydropyrroles, respectively (the latter via an Alder-ene reaction). The gold nanoparticles were immobilized on thiol-functionalized microcrystalline cellulose and characterized by electron microscopy (HAADF-STEM) and by XPS. The thiol-stabilized gold nanoparticles (Au-0) were obtained in the size range 1.5-6 nm at the cellulose surface. The robust and sustainable cellulose-supported gold nanocatalyst can be recycled for multiple cycles without losing activity.

Emneord
cellulose-supported nanogold catalysis, C-C bondformation, heterogeneous catalysis, cycloisomerization, heterocycles, Alder-ene reaction
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-223193 (URN)10.1021/acscatal.3c02722 (DOI)001066876500001 ()37560186 (PubMedID)2-s2.0-85167895594 (Scopus ID)
Tilgjengelig fra: 2023-10-24 Laget: 2023-10-24 Sist oppdatert: 2023-10-24bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0001-7286-1211