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Santos-Carballal D, de Leeuw NH. Catalytic formation of oxalic acid on the partially oxidised greigite Fe 3S 4(001) surface. Phys Chem Chem Phys 2022; 24:20104-20124. [PMID: 35983830 DOI: 10.1039/d2cp00333c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Greigite (Fe3S4), with its ferredoxin-like 4Fe-4S redox centres, is a naturally occurring mineral capable of acting as a catalyst in the conversion of carbon dioxide (CO2) into low molecular-weight organic acids (LMWOAs), which are of paramount significance in several soil and plant processes as well as in the chemical industry. In this paper, we report the reaction between CO2 and water (H2O) to form oxalic acid (H2C2O4) on the partially oxidised greigite Fe3S4(001) surface by means of spin-polarised density functional theory calculations with on-site Coulomb corrections and long-range dispersion interactions (DFT+U-D2). We have calculated the bulk phase of Fe3S4 and the two reconstructed Tasker type 3 terminations of its (001) surface, whose properties are in good agreement with available experimental data. We have obtained the relevant phase diagram, showing that the Fe3S4(001) surface becomes 62.5% partially oxidised, by replacing S by O atoms, in the presence of water at the typical conditions of calcination [Mitchell et al. Faraday Discuss. 2021, 230, 30-51]. The adsorption and co-adsorption of the reactants on the partially oxidised Fe3S4(001) surface are exothermic processes. We have considered three mechanistic pathways to explain the formation of H2C2O4, showing that the coupling of the C-C bond and second protonation are the elementary steps with the largest energy penalty. Our calculations suggest that the partially oxidised Fe3S4(001) surface is a mineral phase that can catalyse the formation of H2C2O4 under favourable conditions, which has important implications for natural ecosystems and is a process that can be harnessed for the industrial manufacture of this organic acid.
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Affiliation(s)
| | - Nora H de Leeuw
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK. .,Department of Earth Sciences, Utrecht University, Princetonplein 8A, 3584 CD Utrecht, The Netherlands.
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Ramogayana B, Santos-Carballal D, Maenetja KP, de Leeuw NH, Ngoepe PE. Density Functional Theory Study of Ethylene Carbonate Adsorption on the (0001) Surface of Aluminum Oxide α-Al 2O 3. ACS OMEGA 2021; 6:29577-29587. [PMID: 34778629 PMCID: PMC8582038 DOI: 10.1021/acsomega.1c03771] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Surface coating is one of the techniques used to improve the electrochemical performance and enhance the resistance against decomposition of cathode materials in lithium-ion batteries. Despite several experimental studies addressing the surface coating of secondary Li-ion batteries using α-Al2O3, the reactivity of the material toward the electrolyte components is not yet fully understood. Here, we have employed calculations based on the density functional theory to investigate the adsorption of the organic solvent ethylene carbonate (EC) on the major α-Al2O3(0001) surface. During adsorption of a single EC molecule, it was found that it prefers to bind parallel to the surface through its carboxyl oxygen. As the surface coverage (θ) was increased up to a monolayer, we observed larger adsorption energies per EC molecule (E ads/N EC) for parallel interactions and a reduction for perpendicular interactions. We also noted that increasing the surface coverage with both parallel and perpendicularly interacting EC molecules led to a decrease of the surface free energies and hence increased stability of the α-Al2O3(0001) surface. Despite the larger E ads/N EC observed when the molecule was placed parallel to the surface, minimal charge transfer was calculated for single EC interactions and at higher surface coverages. The simulated scanning tunneling microscopy images are also presented for a clean corundum α-Al2O3 surface and after adsorption with different coverages of parallel and perpendicularly placed EC molecules.
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Affiliation(s)
- Brian Ramogayana
- Materials
Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - David Santos-Carballal
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
| | - Khomotso P. Maenetja
- Materials
Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - Nora H. de Leeuw
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
- Department
of Earth Sciences, Utrecht University, Princetonlaan 8a, Utrecht 3584 CB, The Netherlands
| | - Phuti E. Ngoepe
- Materials
Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
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Mitchell CE, Santos-Carballal D, Beale AM, Jones W, Morgan DJ, Sankar M, de Leeuw NH. The role of surface oxidation and Fe-Ni synergy in Fe-Ni-S catalysts for CO 2 hydrogenation. Faraday Discuss 2021; 230:30-51. [PMID: 33884381 DOI: 10.1039/d0fd00137f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Increasing carbon dioxide (CO2) emissions, resulting in climate change, have driven the motivation to achieve the effective and sustainable conversion of CO2 into useful chemicals and fuels. Taking inspiration from biological processes, synthetic iron-nickel-sulfides have been proposed as suitable catalysts for the hydrogenation of CO2. In order to experimentally validate this hypothesis, here we report violarite (Fe,Ni)3S4 as a cheap and economically viable catalyst for the hydrogenation of CO2 into formate under mild, alkaline conditions at 125 °C and 20 bar (CO2 : H2 = 1 : 1). Calcination of violarite at 200 °C resulted in excellent catalytic activity, far superior to that of Fe-only and Ni-only sulfides. We further report first principles simulations of the CO2 conversion on the partially oxidised (001) and (111) surfaces of stoichiometric violarite (FeNi2S4) and polydymite (Ni3S4) to rationalise the experimentally observed trends. We have obtained the thermodynamic and kinetic profiles for the reaction of carbon dioxide (CO2) and water (H2O) on the catalyst surfaces via substitution and dissociation mechanisms. We report that the partially oxidised (111) surface of FeNi2S4 is the best catalyst in the series and that the dissociation mechanism is the most favourable. Our study reveals that the partial oxidation of the FeNi2S4 surface, as well as the synergy of the Fe and Ni ions, are important in the catalytic activity of the material for the effective hydrogenation of CO2 to formate.
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Affiliation(s)
- Claire E Mitchell
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK.
| | | | - Andrew M Beale
- Department of Chemistry, University College London, London, WC1H 0AJ, UK and Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science & Innovation Campus, Harwell, Didcot, OX11 0FA, UK
| | - Wilm Jones
- Department of Chemistry, University College London, London, WC1H 0AJ, UK and Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science & Innovation Campus, Harwell, Didcot, OX11 0FA, UK
| | - David J Morgan
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK.
| | | | - Nora H de Leeuw
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK. and School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. and Department of Earth Sciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands
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