1
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Cui J, Daboczi M, Cui Z, Gong M, Flitcroft J, Skelton J, Parker SC, Eslava S. BiVO 4 Photoanodes Enhanced with Metal Phosphide Co-Catalysts: Relevant Properties to Boost Photoanode Performance. Small 2024; 20:e2306757. [PMID: 37803928 DOI: 10.1002/smll.202306757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/05/2023] [Indexed: 10/08/2023]
Abstract
Achieving highly performant photoanodes for oxygen evolution is key to developing photoelectrochemical devices for solar water splitting. In this work, BiVO4 photoanodes are enhanced with a series of core-shell structured bimetallic nickel-cobalt phosphides (MPs), and key insights into the role of co-catalysts are provided. The best BiVO4 /Ni1.5 Co0.5 P and BiVO4 /Ni0.5 Co1.5 P photoanodes achieve a 3.5-fold increase in photocurrent compared with bare BiVO4 . It is discovered that this enhanced performance arises from a synergy between work function, catalytic activity, and capacitive ability of the MPs. Distribution of relaxation times analysis reveals that the contact between the MPs, BiVO4 , and the electrolyte gives rise to three routes for hole injection into the electrolyte, all of which are significantly improved by the presence of a second metal cation in the co-catalyst. Kinetic studies demonstrate that the significantly improved interfacial charge injection is due to a lower charge-transfer resistance, enhanced oxygen-evolution reaction kinetics, and larger surface hole concentrations, providing deeper insights into the carrier dynamics in these photoanode/co-catalyst systems for their rational design.
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Affiliation(s)
- Junyi Cui
- Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Matyas Daboczi
- Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Zhenyu Cui
- Chu Kochen Honors College, Zhejiang University, Hangzhou, 310058, China
| | - Mengjun Gong
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK
| | - Joseph Flitcroft
- Department of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | - Jonathan Skelton
- Department of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | | | - Salvador Eslava
- Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
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2
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Manning JRH, Donval G, Tolladay M, Underwood TL, Parker SC, Düren T. Identifying pathways to metal-organic framework collapse during solvent activation with molecular simulations. J Mater Chem A Mater 2023; 11:25929-25937. [PMID: 38059071 PMCID: PMC10697055 DOI: 10.1039/d3ta04647h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/09/2023] [Indexed: 12/08/2023]
Abstract
Metal-organic framework (MOF) materials are a vast family of nanoporous solids with potential applications ranging from drug delivery to environmental remediation. Application of MOFs in these scenarios is hindered, however, by difficulties in MOF 'activation' after initial synthesis - removal of the synthesis solvent from the pores to make the pore space accessible - often leading to framework collapse if improperly performed. While experimental studies have correlated collapse to specific solvent properties and conditions, the mechanism of activation-collapse is currently unknown. Developing this understanding would enable researchers to create better activation protocols for MOFs, accelerating discovery and process intensification. To achieve this goal, we simulated solvent removal using grand-canonical Monte Carlo and free energy perturbation methods. By framing activation as a fluid desorption problem, we investigated activation processes in the isoreticular metal organic framework (IRMOF) family of MOFs for different solvents. We identified two pathways for solvent activation - the solvent either desorbs uniformly from each individual pore or forms coexisting phases during desorption. These mesophases in turn lead to large capillary stresses within the framework, corroborating experimental hypotheses for the cause of activation-collapse. Finally, we found that the activation energy of solvent removal increased with pore size and connectivity due to the increased stability of solvent mesophases, matching experimental findings. Using these simulations, it is possible to screen MOF activation procedures, enabling rapid identification of ideal solvents and conditions and thus enabling faster development of MOFs for practical applications.
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Affiliation(s)
- Joseph R H Manning
- Centre for Integrated Materials, Processes and Structures, Department of Chemical Engineering, University of Bath UK
- Department of Chemistry, University College London UK
- Department of Chemical Engineering, University of Manchester UK
| | - Gaël Donval
- Centre for Integrated Materials, Processes and Structures, Department of Chemical Engineering, University of Bath UK
| | - Mat Tolladay
- Centre for Integrated Materials, Processes and Structures, Department of Chemical Engineering, University of Bath UK
| | | | | | - Tina Düren
- Centre for Integrated Materials, Processes and Structures, Department of Chemical Engineering, University of Bath UK
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3
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Ta KM, Cooke DJ, Gillie LJ, Parker SC, Seal S, Wilson PB, Phillips RM, Skelton JM, Molinari M. Infrared and Raman Diagnostic Modeling of Phosphate Adsorption on Ceria Nanoparticles. J Phys Chem C Nanomater Interfaces 2023; 127:20183-20193. [PMID: 37850082 PMCID: PMC10577678 DOI: 10.1021/acs.jpcc.3c05409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/08/2023] [Indexed: 10/19/2023]
Abstract
Cerium dioxide (CeO2; ceria) nanoparticles (CeNPs) are promising nanozymes that show a variety of biological activity. Effective nanozymes need to retain their activity in the face of surface speciation in biological environments, and characterizing surface speciation is therefore critical to understanding and controlling the therapeutic capabilities of CeNPs. In particular, adsorbed phosphates can impact the enzymatic activity exploited to convert phosphate prodrugs into therapeutics in vivo and also define the early stages of the phosphate-scavenging processes that lead to the transformation of active CeO2 into inactive CePO4. In this work, we utilize ab initio lattice-dynamics calculations to study the interaction of phosphates with the three major surfaces of ceria and to predict the infrared (IR) and Raman spectral signatures of adsorbed phosphate species. We find that phosphates adsorb strongly to CeO2 surfaces in a range of stable binding configurations, of which 5-fold coordinated P species in a trigonal bipyramidal coordination may represent a stable intermediate in the early stages of phosphate scavenging. We find that the phosphate species show characteristic spectral fingerprints between 500 and 1500 cm-1, whereas the bare CeO2 surfaces show no active modes above 600 cm-1, and the 5-fold coordinated P species in particular show potential diagnostic P-O stretching modes between 650 and 700 cm-1 in both IR and Raman spectra. This comprehensive exploration of different binding modes for phosphates on CeO2 and the set of reference spectra provides an important step toward the experimental characterization of phosphate speciation and, ultimately, control of its impact on the performance of ceria nanozymes.
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Affiliation(s)
- Khoa Minh Ta
- Department
of Chemistry, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - David J. Cooke
- Department
of Chemistry, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - Lisa J. Gillie
- Department
of Chemistry, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - Stephen C. Parker
- Department
of Chemistry, University of Bath, Claverton
Down, Bath BA2 7AY, U.K.
| | - Sudipta Seal
- Department
of Materials Science & Engineering, Advanced Materials Processing
and Analysis Centre (AMPAC), Nanoscience Technology Centre (NSTC), University of Central Florida, Orlando, Florida 32816, United States
- Bionix
Cluster, College of Medicine, University
of Central Florida, Orlando, Florida 32827, United States
| | - Philippe B. Wilson
- School
of Animal, Rural and Environmental Sciences, Brackenhurst Campus, Nottingham Trent University, Southwell NG25 0QF, U.K.
| | - Roger M. Phillips
- Department
of Pharmacy, School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH, U.K.
| | | | - Marco Molinari
- Department
of Chemistry, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
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4
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Tse JS, Grant J, Skelton JM, Gillie LJ, Zhu R, Pesce GL, Ball RJ, Parker SC, Molinari M. Location of Artinite (Mg 2CO 3(OH) 2·3H 2O) within the MgO-CO 2-H 2O system using ab initio thermodynamics. Phys Chem Chem Phys 2023. [PMID: 37377444 DOI: 10.1039/d3cp00518f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The MgO-CO2-H2O system have a variety of important industrial applications including in catalysis, immobilisation of radionuclides and heavy metals, construction, and mineralisation and permanent storage of anthropogenic CO2. Here, we develop a computational approach to generate phase stability plots for the MgO-CO2-H2O system that do not rely on traditional experimental corrections for the solid phases. We compare the predictions made by several dispersion-corrected density-functional theory schemes, and we include the temperature-dependent Gibbs free energy through the quasi-harmonic approximation. We locate the Artinite phase (Mg2CO3(OH)2·3H2O) within the MgO-CO2-H2O phase stability plot, and we demonstrate that this widely-overlooked hydrated and carbonated phase is metastable and can be stabilised by inhibiting the formation of fully-carbonated stable phases. Similar considerations may apply more broadly to other lesser known phases. These findings provide new insight to explain conflicting results from experimental studies, and demonstrate how this phase can potentially be stabilised by optimising the synthesis conditions.
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Affiliation(s)
- Joshua S Tse
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - James Grant
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Jonathan M Skelton
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Lisa J Gillie
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Runliang Zhu
- CAS Key Laboratory of Mineralogy and Metallogeny, and Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
| | - Giovanni L Pesce
- Department of Mechanical and Construction Engineering, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Richard J Ball
- Department of Architecture and Civil Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Marco Molinari
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
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5
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Calì E, Thomas MP, Vasudevan R, Wu J, Gavalda-Diaz O, Marquardt K, Saiz E, Neagu D, Unocic RR, Parker SC, Guiton BS, Payne DJ. Real-time insight into the multistage mechanism of nanoparticle exsolution from a perovskite host surface. Nat Commun 2023; 14:1754. [PMID: 36990982 DOI: 10.1038/s41467-023-37212-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
In exsolution, nanoparticles form by emerging from oxide hosts by application of redox driving forces, leading to transformative advances in stability, activity, and efficiency over deposition techniques, and resulting in a wide range of new opportunities for catalytic, energy and net-zero-related technologies. However, the mechanism of exsolved nanoparticle nucleation and perovskite structural evolution, has, to date, remained unclear. Herein, we shed light on this elusive process by following in real time Ir nanoparticle emergence from a SrTiO3 host oxide lattice, using in situ high-resolution electron microscopy in combination with computational simulations and machine learning analytics. We show that nucleation occurs via atom clustering, in tandem with host evolution, revealing the participation of surface defects and host lattice restructuring in trapping Ir atoms to initiate nanoparticle formation and growth. These insights provide a theoretical platform and practical recommendations to further the development of highly functional and broadly applicable exsolvable materials.
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Affiliation(s)
- Eleonora Calì
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi, 24, Turin, 10129, Italy.
| | - Melonie P Thomas
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY, 40506, USA
- Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Rama Vasudevan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Ji Wu
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
- School of Physical and Chemical Sciences, Queen Mary University of London, 327 Mile End Road, London, E1 4NS, UK
| | - Oriol Gavalda-Diaz
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
- Composites Research Group, Faculty of Engineering, The University of Nottingham, Nottingham, NG8 1BB, UK
| | - Katharina Marquardt
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - Eduardo Saiz
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - Dragos Neagu
- Chemical & Process Engineering, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Raymond R Unocic
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Beth S Guiton
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY, 40506, USA
| | - David J Payne
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0FA, UK.
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6
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Lightfoot JC, Buchard A, Castro-Dominguez B, Parker SC. Comparative Study of Oxygen Diffusion in Polyethylene Terephthalate and Polyethylene Furanoate Using Molecular Modeling: Computational Insights into the Mechanism for Gas Transport in Bulk Polymer Systems. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jasmine C. Lightfoot
- Centre for Sustainable and Circular Technologies, Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Antoine Buchard
- Centre for Sustainable and Circular Technologies, Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | | | - Stephen C. Parker
- Centre for Sustainable and Circular Technologies, Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
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7
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Wood ND, Teter DM, Tse JS, Jackson RA, Cooke DJ, Gillie LJ, Parker SC, Molinari M. An atomistic modelling investigation of the defect chemistry of SrTiO3 and its Ruddlesden-Popper phases, Srn+1TinO3n+1 (n = 1–3). J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Tse J, Aziz A, Flitcroft J, Skelton JM, Gillie LJ, Parker SC, Cooke DJ, Molinari M. Unraveling the Impact of Graphene Addition to Thermoelectric SrTiO 3 and La-Doped SrTiO 3 Materials: A Density Functional Theory Study. ACS Appl Mater Interfaces 2021; 13:41303-41314. [PMID: 34405998 PMCID: PMC8414480 DOI: 10.1021/acsami.1c10865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/06/2021] [Indexed: 06/12/2023]
Abstract
We present a detailed theoretical investigation of the interaction of graphene with the SrO-terminated (001) surface of pristine and La-doped SrTiO3. The adsorption of graphene is thermodynamically favorable with interfacial adsorption energies of -0.08 and -0.32 J/m2 to pristine SrTiO3 and La-doped SrTiO3 surfaces, respectively. We find that graphene introduces C 2p states at the Fermi level, rendering the composite semimetallic, and thus the electrical properties are predicted to be highly sensitive to the amount and quality of the graphene. An investigation of the lattice dynamics predicts that graphene adsorption may lead to a 60-90% reduction in the thermal conductivity due to a reduction in the phonon group velocities, accounting for the reduced thermal conductivity of the composite materials observed experimentally. This effect is enhanced by La doping. We also find evidence that both La dopant ions and adsorbed graphene introduce low-frequency modes that may scatter heat-carrying acoustic phonons, and that, if present, these effects likely arise from stronger phonon-phonon interactions.
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Affiliation(s)
- Joshua Tse
- Department
of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - Alex Aziz
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - Joseph
M. Flitcroft
- Department
of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Jonathan M. Skelton
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Lisa J. Gillie
- Department
of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | | | - David J. Cooke
- Department
of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - Marco Molinari
- Department
of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
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9
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Kunhi Mohamed A, Moutzouri P, Berruyer P, Walder BJ, Siramanont J, Harris M, Negroni M, Galmarini SC, Parker SC, Scrivener KL, Emsley L, Bowen P. The Atomic-Level Structure of Cementitious Calcium Aluminate Silicate Hydrate. J Am Chem Soc 2020; 142:11060-11071. [PMID: 32406680 DOI: 10.1021/jacs.0c02988] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Despite use of blended cements containing significant amounts of aluminum for over 30 years, the structural nature of aluminum in the main hydration product, calcium aluminate silicate hydrate (C-A-S-H), remains elusive. Using first-principles calculations, we predict that aluminum is incorporated into the bridging sites of the linear silicate chains and that at high Ca:Si and H2O ratios, the stable coordination number of aluminum is six. Specifically, we predict that silicate-bridging [AlO2(OH)4]5- complexes are favored, stabilized by hydroxyl ligands and charge balancing calcium ions in the interlayer space. This structure is then confirmed experimentally by one- and two-dimensional dynamic nuclear polarization enhanced 27Al and 29Si solid-state NMR experiments. We notably assign a narrow 27Al NMR signal at 5 ppm to the silicate-bridging [AlO2(OH)4]5- sites and show that this signal correlates to 29Si NMR signals from silicates in C-A-S-H, conflicting with its conventional assignment to a "third aluminate hydrate" (TAH) phase. We therefore conclude that TAH does not exist. This resolves a long-standing dilemma about the location and nature of the six-fold-coordinated aluminum observed by 27Al NMR in C-A-S-H samples.
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Affiliation(s)
- Aslam Kunhi Mohamed
- Laboratory of Construction Materials, Institut des Matériaux, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Institute for Building Materials, Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Pinelopi Moutzouri
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Pierrick Berruyer
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Brennan J Walder
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jirawan Siramanont
- Laboratory of Construction Materials, Institut des Matériaux, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,SCG CEMENT Co., Ltd., Saraburi 18260, Thailand
| | - Maya Harris
- Laboratory of Construction Materials, Institut des Matériaux, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Mattia Negroni
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sandra C Galmarini
- Building Energy Materials and Components, EMPA, CH-8600 Dübendorf, Switzerland
| | - Stephen C Parker
- Computational Solid State Chemistry Group, Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Karen L Scrivener
- Laboratory of Construction Materials, Institut des Matériaux, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Paul Bowen
- Laboratory of Construction Materials, Institut des Matériaux, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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10
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Skelton JM, Gunn DSD, Metz S, Parker SC. Accuracy of Hybrid Functionals with Non-Self-Consistent Kohn-Sham Orbitals for Predicting the Properties of Semiconductors. J Chem Theory Comput 2020; 16:3543-3557. [PMID: 32369352 DOI: 10.1021/acs.jctc.9b01218] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Accurately modeling the electronic structure of materials is a persistent challenge to high-throughput screening. A promising means of balancing accuracy against computational cost is non-self-consistent calculations with hybrid density-functional theory, where the electronic band energies are evaluated using a hybrid functional from orbitals obtained with a less demanding (semi)local functional. We have quantified the performance of this technique for predicting the physical properties of 16 tetrahedral semiconductors with bandgaps from 0.2 to 5.5 eV. Provided the base functional predicts a nonmetallic electronic structure, bandgaps within 5% of the PBE0 and HSE06 gaps can be obtained with an order of magnitude reduction in computing time. The positions of the valence and conduction band extrema and the Fermi level are well reproduced, enabling calculation of the band dispersion, density of states, and dielectric properties using Fermi's Golden Rule. While the error in the non-self-consistent total energies is ∼50 meV atom-1, the energy-volume curves are reproduced accurately enough to obtain the equilibrium volume and bulk modulus with minimal error. We also test the dielectric-dependent scPBE0 functional and obtain bandgaps and dielectric constants to within 2.5% of the self-consistent results, which amounts to a significant improvement over self-consistent PBE0 for a similar computational cost. We identify cases where the non-self-consistent approach is expected to perform poorly and demonstrate that partial self-consistency provides a practical and efficient workaround. Finally, we perform proof-of-concept calculations on CoO and NiO to demonstrate the applicability of the technique to strongly correlated open-shell transition-metal oxides.
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Affiliation(s)
- Jonathan M Skelton
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.,Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom
| | - David S D Gunn
- STFC Daresbury Laboratory, Keckwick Ln., Daresbury, Warrington WA4 4AD, United Kingdom
| | - Sebastian Metz
- STFC Daresbury Laboratory, Keckwick Ln., Daresbury, Warrington WA4 4AD, United Kingdom.,Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, 79110 Freiburg, Germany
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom
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11
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Moxon S, Symington AR, Tse JS, Dawson J, Flitcroft JM, Parker SC, Cooke DJ, Harker RM, Molinari M. The energetics of carbonated PuO 2 surfaces affects nanoparticle morphology: a DFT+U study. Phys Chem Chem Phys 2020; 22:7728-7737. [PMID: 32191781 DOI: 10.1039/d0cp00021c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radiolytic corrosion of actinide materials represent an issue for the long term storage and disposal of nuclear materials. Molecular species adsorbed at the surface of the actinides may impact the rate of radiolysis, and as the surfaces corrode, the soluble toxic and radioactive species leach into groundwater. It is therefore critical to characterise the surface composition of actinides. Here, we employ ab initio modelling to determine the surface composition of PuO2 with respect to adsorbed CO2. We found that CO2 interacts strongly with the surface forming carbonate species. By mapping the energetics of this interaction, we then calculate the temperature of desorption, finding that surface morphology has a strong impact on the adsorption of CO2, with the {100} being the most and the {111} the least affected by carbonation. Finally, we predict the effect of carbonation on the morphology of PuO2 nanoparticles as a function of temperature and pressure, finding that truncated octahedral is the preferred morphology. This modelling strategy helps characterise surface compensition and nanoparticle morphology, and we discuss the implication for radiolytically driven dispersal of material into the environment.
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Affiliation(s)
- Samuel Moxon
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Adam R Symington
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Joshua S Tse
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - James Dawson
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Joseph M Flitcroft
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - David J Cooke
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | | | - Marco Molinari
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
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12
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Kaub J, Kler J, Parker SC, De Souza RA. The usefulness of molecular-dynamics simulations in clarifying the activation enthalpy of oxygen-vacancy migration in the perovskite oxide BaTiO 3. Phys Chem Chem Phys 2020; 22:5413-5417. [PMID: 32104813 DOI: 10.1039/c9cp06838d] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We employed molecular-dynamics simulations with interatomic pair-potentials to examine oxygen-vacancy diffusion in the cubic phase of perovskite BaTiO3 as a function of temperature. By comparing the absolute rate of vacancy diffusion as well as its temperature dependence with experimental data, we are able to narrow down the activation enthalpy of migration to 0.70-0.76 eV.
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Affiliation(s)
- Johannes Kaub
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany.
| | - Joe Kler
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany.
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath, Avon, UK
| | - Roger A De Souza
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany.
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13
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Putra BR, Szot-Karpińska K, Kudła P, Yin H, Boswell JA, Squires AM, Da Silva MA, Edler KJ, Fletcher PJ, Parker SC, Marken F. Bacteriophage M13 Aggregation on a Microhole Poly(ethylene terephthalate) Substrate Produces an Anionic Current Rectifier: Sensitivity toward Anionic versus Cationic Guests. ACS Appl Bio Mater 2019; 3:512-521. [DOI: 10.1021/acsabm.9b00952] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Budi Riza Putra
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Bogor 16680, West Java, Indonesia
| | - Katarzyna Szot-Karpińska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Patryk Kudła
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Han Yin
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
| | - Jacob A. Boswell
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
| | - Adam M. Squires
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
| | | | - Karen J. Edler
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
| | - Philip J. Fletcher
- Material & Chemical Characterisation Facility MC2, University of Bath, Bath BA2 7AY, U.K
| | - Stephen C. Parker
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
| | - Frank Marken
- Department of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K
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14
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McCluskey AR, Grant J, Symington AR, Snow T, Doutch J, Morgan BJ, Parker SC, Edler KJ. An introduction to classical molecular dynamics simulation for experimental scattering users. J Appl Crystallogr 2019; 52:665-668. [PMID: 31236095 PMCID: PMC6557182 DOI: 10.1107/s1600576719004333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/30/2019] [Indexed: 11/10/2022] Open
Abstract
Classical molecular dynamics simulations are a common component of multi-modal analyses of scattering measurements, such as small-angle scattering and diffraction. Users of these experimental techniques often have no formal training in the theory and practice of molecular dynamics simulation, leading to the possibility of these simulations being treated as a `black box' analysis technique. This article describes an open educational resource (OER) designed to introduce classical molecular dynamics to users of scattering methods. This resource is available as a series of interactive web pages, which can be easily accessed by students, and as an open-source software repository, which can be freely copied, modified and redistributed by educators. The topics covered in this OER include classical atomistic modelling, parameterizing interatomic potentials, molecular dynamics simulations, typical sources of error and some of the approaches to using simulations in the analysis of scattering data.
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15
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Gunn DD, Skelton JM, Burton LA, Metz S, Parker SC. Thermodynamics, Electronic Structure, and Vibrational Properties of Sn n (S 1-x Se x ) m Solid Solutions for Energy Applications. Chem Mater 2019; 31:3672-3685. [PMID: 32063672 PMCID: PMC7011755 DOI: 10.1021/acs.chemmater.9b00362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/02/2019] [Indexed: 06/10/2023]
Abstract
The tin sulfides and selenides have a range of applications spanning photovoltaics and thermoelectrics to photocatalysts and photodetectors. However, significant challenges remain to widespread use, including electrical and chemical incompatibilities between SnS and device contact materials and the environmental toxicity of selenium. Solid solutions of isostructural sulfide and selenide phases could provide scope for optimizing physical properties against sustainability requirements, but this has not been comprehensively explored. This work presents a detailed modeling study of the Pnma and rocksalt Sn(S1-x Se x ), Sn(S1-x Se x )2, and Sn2(S1-x Se x )3 solid solutions. All four show an energetically favorable and homogenous mixing at all compositions, but rocksalt Sn(S1-x Se x ) and Sn2(S1-x Se x )3 are predicted to be metastable and accessible only under certain synthesis conditions. Alloying leads to a predictable variation of the bandgap, density of states, and optical properties with composition, allowing SnS2 to be "tuned down" to the ideal Shockley-Queisser bandgap of 1.34 eV. The impact of forming the solid solutions on the lattice dynamics is also investigated, providing insight into the enhanced performance of Sn(S1-x Se x ) solid solutions for thermoelectric applications. These results demonstrate that alloying affords facile and precise control over the electronic, optical, and vibrational properties, allowing material performance for optoelectronic applications to be optimized alongside a variety of practical considerations.
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Affiliation(s)
- David
S. D. Gunn
- STFC
Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington WA4 4AD, U.K.
| | - Jonathan M. Skelton
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
1AG, U.K.
| | - Lee A. Burton
- Institute
of Condensed Matter and Nanosciences, Université
Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Sebastian Metz
- STFC
Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington WA4 4AD, U.K.
| | - Stephen C. Parker
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
1AG, U.K.
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16
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Flitcroft JM, Symington AR, Molinari M, Brincat NA, Williams NR, Parker SC. Impact of Hydrogen on the Intermediate Oxygen Clusters and Diffusion in Fluorite Structured UO 2+ x. Inorg Chem 2019; 58:3774-3779. [PMID: 30835457 DOI: 10.1021/acs.inorgchem.8b03317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Uranium dioxide is the most prevalent nuclear fuel. Defect clusters are known to be present in significant concentrations in hyperstoichoimetric uranium oxide, UO2+ x, and have a significant impact on the corrosion of the material. A detailed understanding of the defect clusters that form is required for accurate diffusion models in UO2+ x. Using ab initio calculations, we show that at low excess oxygen concentration, where defects are mostly isolated oxygen interstitials, hydrogen stabilizes the initial clustering. The simplest cluster at this low excess oxygen stoichiometry consists of a pair of oxygen ions bound to an oxygen vacancy, namely the split mono-interstital, which resembles larger split interstitials clusters in UO2+ x. Our data shows that, depending on local hydrogen concertation, the presence of hydrogen stabilizes this cluster over isolated oxygen interstitials.
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Affiliation(s)
- Joseph M Flitcroft
- Department of Chemistry , University of Huddersfield , Queensgate , Huddersfield HD1 3DH , United Kingdom.,Department of Chemistry , University of Bath , Bath BA2 7AY , United Kingdom
| | - Adam R Symington
- Department of Chemistry , University of Bath , Bath BA2 7AY , United Kingdom
| | - Marco Molinari
- Department of Chemistry , University of Huddersfield , Queensgate , Huddersfield HD1 3DH , United Kingdom
| | | | | | - Stephen C Parker
- Department of Chemistry , University of Bath , Bath BA2 7AY , United Kingdom
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17
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Molinari M, Symington AR, Sayle DC, Sakthivel TS, Seal S, Parker SC. Computer-Aided Design of Nanoceria Structures as Enzyme Mimetic Agents: The Role of Bodily Electrolytes on Maximizing Their Activity. ACS Appl Bio Mater 2019; 2:1098-1106. [DOI: 10.1021/acsabm.8b00709] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Marco Molinari
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Adam R. Symington
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Dean C. Sayle
- School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, United Kingdom
| | - Tamil S. Sakthivel
- Department of Materials Science and Engineering, Advanced Materials Processing and Analysis Center, Nanoscience and Tehcnology Center, University of Central Florida, Orlando, Florida 32816, United States
| | - Sudipta Seal
- Department of Materials Science and Engineering, Advanced Materials Processing and Analysis Center, Nanoscience and Tehcnology Center, University of Central Florida, Orlando, Florida 32816, United States
- College of Medicine, University of Central Florida, Orlando, Florida 32827, United States
| | - Stephen C. Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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18
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Jones CL, Skelton JM, Parker SC, Raithby PR, Walsh A, Wilson CC, Thomas LH. Living in the salt-cocrystal continuum: indecisive organic complexes with thermochromic behaviour. CrystEngComm 2019. [DOI: 10.1039/c8ce02066c] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The thermochromic behaviour of the haloaniline – 3,5-dinotrobenzoic acid cocrystals over the temperature range from 30–108 °C.
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Affiliation(s)
| | | | - Stephen C. Parker
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
- School of Chemistry
| | | | - Aron Walsh
- Department of Materials
- Imperial College, London
- London SW7 2AZ
- UK
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19
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McCluskey AR, Sanchez-Fernandez A, Edler KJ, Parker SC, Jackson AJ, Campbell RA, Arnold T. Bayesian determination of the effect of a deep eutectic solvent on the structure of lipid monolayers. Phys Chem Chem Phys 2019; 21:6133-6141. [DOI: 10.1039/c9cp00203k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A novel reflectometry analysis method reveals the structure of lipid monolayers at the air-DES interface.
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Affiliation(s)
| | | | | | | | - Andrew J. Jackson
- European Spallation Source
- SE-211 00 Lund
- Sweden
- Department of Physical Chemistry
- Lund University
| | - Richard A. Campbell
- Division of Pharmacy and Optometry
- University of Manchester
- Manchester
- UK
- Institut Laue-Langevin
| | - Thomas Arnold
- Department of Chemistry
- University of Bath
- Bath
- UK
- Diamond Light Source
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20
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Yeandel SR, Molinari M, Parker SC. The impact of tilt grain boundaries on the thermal transport in perovskite SrTiO 3 layered nanostructures. A computational study. Nanoscale 2018; 10:15010-15022. [PMID: 30052247 DOI: 10.1039/c8nr02234h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thermal management at solid interfaces presents a technological challenge for modern thermoelectric power generation. Here, we define a computational protocol to identify nanoscale structural features that can facilitate thermal transport in technologically important nanostructured materials. We consider the highly promising thermoelectric material, SrTiO3, where tilt grain boundaries lower thermal conductivity. The magnitude of the reduction is shown to depend on compositional and structural arrangements at the solid interface. Quantitative analysis indicates that layered nanostructures less than 10 nm will be required to significantly reduce the thermal conductivity below the bulk value, and it will be virtually independent of temperature for films less than 2 nm depending on the orientation with a reduction of thermal transport up to 75%. At the nanoscale, the vibrational response of nanostructures shows concerted vibrations between the grain boundary and inter-boundary regions. As the grain boundary acts markedly as a phonon quencher, we predict that any manipulation of nanostructures to further reduce thermal conductivity will be more beneficial if applied to the inter-boundary region. Our findings may be applied more widely to benefit other technological applications where efficient thermal transport is important.
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Affiliation(s)
- Stephen R Yeandel
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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21
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Skelton JM, Burton LA, Jackson AJ, Oba F, Parker SC, Walsh A. Lattice dynamics of the tin sulphides SnS 2, SnS and Sn 2S 3: vibrational spectra and thermal transport. Phys Chem Chem Phys 2018; 19:12452-12465. [PMID: 28470289 PMCID: PMC5450010 DOI: 10.1039/c7cp01680h] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
First-principles lattice-dynamics calculations are used to model and compare the vibrational spectra and thermal transport of four bulk tin-sulphide materials.
We present an in-depth first-principles study of the lattice dynamics of the tin sulphides SnS2, Pnma and π-cubic SnS and Sn2S3. An analysis of the harmonic phonon dispersion and vibrational density of states reveals phonon bandgaps between low- and high-frequency modes consisting of Sn and S motion, respectively, and evidences a bond-strength hierarchy in the low-dimensional SnS2, Pnma SnS and Sn2S3 crystals. We model and perform a complete characterisation of the infrared and Raman spectra, including temperature-dependent anharmonic linewidths calculated using many-body perturbation theory. We illustrate how vibrational spectroscopy could be used to identify and characterise phase impurities in tin sulphide samples. The spectral linewidths are used to model the thermal transport, and the calculations indicate that the low-dimensional Sn2S3 has a very low lattice thermal conductivity, potentially giving it superior performance to SnS as a candidate thermoelectric material.
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Affiliation(s)
- Jonathan M Skelton
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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22
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Kepaptsoglou D, Baran JD, Azough F, Ekren D, Srivastava D, Molinari M, Parker SC, Ramasse QM, Freer R. Prospects for Engineering Thermoelectric Properties in La 1/3NbO 3 Ceramics Revealed via Atomic-Level Characterization and Modeling. Inorg Chem 2017; 57:45-55. [PMID: 29257680 DOI: 10.1021/acs.inorgchem.7b01584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of experimental and computational techniques has been employed to explore the crystal structure and thermoelectric properties of A-site-deficient perovskite La1/3NbO3 ceramics. Crystallographic data from X-ray and electron diffraction confirmed that the room temperature structure is orthorhombic with Cmmm as a space group. Atomically resolved imaging and analysis showed that there are two distinct A sites: one is occupied with La and vacancies, and the second site is fully unoccupied. The diffuse superstructure reflections observed through diffraction techniques are shown to originate from La vacancy ordering. La1/3NbO3 ceramics sintered in air showed promising high-temperature thermoelectric properties with a high Seebeck coefficient of S1 = -650 to -700 μV/K and a low and temperature-stable thermal conductivity of k = 2-2.2 W/m·K in the temperature range of 300-1000 K. First-principles electronic structure calculations are used to link the temperature dependence of the Seebeck coefficient measured experimentally to the evolution of the density of states with temperature and indicate possible avenues for further optimization through electron doping and control of the A-site occupancies. Moreover, lattice thermal conductivity calculations give insights into the dependence of the thermal conductivity on specific crystallographic directions of the material, which could be exploited via nanostructuring to create high-efficiency compound thermoelectrics.
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Affiliation(s)
| | - Jakub D Baran
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Feridoon Azough
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Dursun Ekren
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | | | - Marco Molinari
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K.,Department of Chemistry, University of Huddersfield , Huddersfield HD1 3DH, U.K
| | - Stephen C Parker
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus , Daresbury WA4 4AD, U.K
| | - Robert Freer
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
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23
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Azough F, Jackson SS, Ekren D, Freer R, Molinari M, Yeandel SR, Panchmatia PM, Parker SC, Maldonado DH, Kepaptsoglou DM, Ramasse QM. Concurrent La and A-Site Vacancy Doping Modulates the Thermoelectric Response of SrTiO 3: Experimental and Computational Evidence. ACS Appl Mater Interfaces 2017; 9:41988-42000. [PMID: 29134804 DOI: 10.1021/acsami.7b14231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To help understand the factors controlling the performance of one of the most promising n-type oxide thermoelectric SrTiO3, we need to explore structural control at the atomic level. In Sr1-xLa2x/3TiO3 ceramics (0.0 ≤ x ≤ 0.9), we determined that the thermal conductivity can be reduced and controlled through an interplay of La-substitution and A-site vacancies and the formation of a layered structure. The decrease in thermal conductivity with La and A-site vacancy substitution dominates the trend in the overall thermoelectric response. The maximum dimensionless figure of merit is 0.27 at 1070 K for composition x = 0.50 where half of the A-sites are occupied with La and vacancies. Atomic resolution Z-contrast imaging and atomic scale chemical analysis show that as the La content increases, A-site vacancies initially distribute randomly (x < 0.3), then cluster (x ≈ 0.5), and finally form layers (x = 0.9). The layering is accompanied by a structural phase transformation from cubic to orthorhombic and the formation of 90° rotational twins and antiphase boundaries, leading to the formation of localized supercells. The distribution of La and A-site vacancies contributes to a nonuniform distribution of atomic scale features. This combination induces temperature stable behavior in the material and reduces thermal conductivity, an important route to enhancement of the thermoelectric performance. A computational study confirmed that the thermal conductivity of SrTiO3 is lowered by the introduction of La and A-site vacancies as shown by the experiments. The modeling supports that a critical mass of A-site vacancies is needed to reduce thermal conductivity and that the arrangement of La, Sr, and A-site vacancies has a significant impact on thermal conductivity only at high La concentration.
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Affiliation(s)
- Feridoon Azough
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Samuel S Jackson
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Dursun Ekren
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Robert Freer
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Marco Molinari
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
- Department of Chemistry, University of Huddersfield , Queensgate, Huddersfield HD1 3DH, U.K
| | - Stephen R Yeandel
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
- Department of Chemistry, Loughborough University , Epinal Way, Loughborough LE11 3TU, U.K
| | - Pooja M Panchmatia
- Department of Chemistry, Loughborough University , Epinal Way, Loughborough LE11 3TU, U.K
| | - Stephen C Parker
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | | | - Demie M Kepaptsoglou
- SuperSTEM Laboratory , SciTech Daresbury Campus, Keckwick Lane, Warrington WA4 4AD, U.K
| | - Quentin M Ramasse
- SuperSTEM Laboratory , SciTech Daresbury Campus, Keckwick Lane, Warrington WA4 4AD, U.K
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24
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Affiliation(s)
- Marco Molinari
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom
| | - Nicholas A. Brincat
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
- AWE Public Limited Company, Aldermaston, Reading RG7 4PR, United Kingdom
| | - Geoffrey C. Allen
- AWE Public Limited Company, Aldermaston, Reading RG7 4PR, United Kingdom
- Interface
Analysis Center, University of Bristol, Bristol, United Kingdom
| | - Stephen C. Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
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25
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Woodall CH, Christensen J, Skelton JM, Hatcher LE, Parlett A, Raithby PR, Walsh A, Parker SC, Beavers CM, Teat SJ, Intissar M, Reber C, Allan DR. Observation of a re-entrant phase transition in the molecular complex tris(μ 2-3,5-diiso-propyl-1,2,4-triazolato-κ 2N1: N2)trigold(I) under high pressure. IUCrJ 2016; 3:367-376. [PMID: 28461897 PMCID: PMC5391858 DOI: 10.1107/s2052252516013129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 08/15/2016] [Indexed: 06/07/2023]
Abstract
We report a molecular crystal that exhibits four successive phase transitions under hydro-static pressure, driven by aurophilic interactions, with the ground-state structure re-emerging at high pressure. The effect of pressure on two polytypes of tris(μ2-3,5-diiso-propyl-1,2,4-triazolato-κ2N1:N2)trigold(I) (denoted Form-I and Form-II) has been analysed using luminescence spectroscopy, single-crystal X-ray diffraction and first-principles computation. A unique phase behaviour was observed in Form-I, with a complex sequence of phase transitions between 1 and 3.5 GPa. The ambient C2/c mother cell transforms to a P21/n phase above 1 GPa, followed by a P21/a phase above 2 GPa and a large-volume C2/c supercell at 2.70 GPa, with the previously observed P21/n phase then reappearing at higher pressure. The observation of crystallographically identical low- and high-pressure P21/n phases makes this a rare example of a re-entrant phase transformation. The phase behaviour has been characterized using detailed crystallographic theory and modelling, and rationalized in terms of molecular structural distortions. The dramatic changes in conformation are correlated with shifts of the luminescence maxima, from a band maximum at 14040 cm-1 at 2.40 GPa, decreasing steeply to 13550 cm-1 at 3 GPa. A similar study of Form-II displays more conventional crystallographic behaviour, indicating that the complex behaviour observed in Form-I is likely to be a direct consequence of the differences in crystal packing between the two polytypes.
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Affiliation(s)
| | - Jeppe Christensen
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | | | | | - Andrew Parlett
- Department of Chemistry, University of Bath, Bath BA2 7AY, UK
| | - Paul R. Raithby
- Department of Chemistry, University of Bath, Bath BA2 7AY, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | - Aron Walsh
- Department of Chemistry, University of Bath, Bath BA2 7AY, UK
| | | | - Christine M. Beavers
- Station 11.3.1, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Simon J. Teat
- Station 11.3.1, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Mourad Intissar
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Christian Reber
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - David R. Allan
- Station I19, Diamond Light Source, Didcot, Oxfordshire, OX11 0QX, UK
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26
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Skelton JM, Burton LA, Parker SC, Walsh A, Kim CE, Soon A, Buckeridge J, Sokol AA, Catlow CRA, Togo A, Tanaka I. Anharmonicity in the High-Temperature Cmcm Phase of SnSe: Soft Modes and Three-Phonon Interactions. Phys Rev Lett 2016; 117:075502. [PMID: 27563974 DOI: 10.1103/physrevlett.117.075502] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Indexed: 05/21/2023]
Abstract
The layered semiconductor SnSe is one of the highest-performing thermoelectric materials known. We demonstrate, through a first-principles lattice-dynamics study, that the high-temperature Cmcm phase is a dynamic average over lower-symmetry minima separated by very small energetic barriers. Compared to the low-temperature Pnma phase, the Cmcm phase displays a phonon softening and enhanced three-phonon scattering, leading to an anharmonic damping of the low-frequency modes and hence the thermal transport. We develop a renormalization scheme to quantify the effect of the soft modes on the calculated properties, and confirm that the anharmonicity is an inherent feature of the Cmcm phase. These results suggest a design concept for thermal insulators and thermoelectric materials, based on displacive instabilities, and highlight the power of lattice-dynamics calculations for materials characterization.
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Affiliation(s)
- Jonathan M Skelton
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Lee A Burton
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Aron Walsh
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Chang-Eun Kim
- Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea
| | - Aloysius Soon
- Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea
| | - John Buckeridge
- University College London, Kathleen Lonsdale Materials Chemistry, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Alexey A Sokol
- University College London, Kathleen Lonsdale Materials Chemistry, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - C Richard A Catlow
- University College London, Kathleen Lonsdale Materials Chemistry, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Atsushi Togo
- Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto Prefecture 606-8501, Japan
| | - Isao Tanaka
- Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto Prefecture 606-8501, Japan
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Srivastava D, Azough F, Freer R, Combe E, Funahashi R, Kepaptsoglou DM, Ramasse QM, Molinari M, Yeandel SR, Baran JD, Parker SC. Crystal structure and thermoelectric properties of Sr-Mo substituted CaMnO 3: a combined experimental and computational study. J Mater Chem C Mater 2015; 3:12245-12259. [PMID: 28496979 PMCID: PMC5361175 DOI: 10.1039/c5tc02318a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/30/2015] [Indexed: 06/07/2023]
Abstract
A combination of experimental and computational techniques has been employed to study doping effects in perovskite CaMnO3. High quality Sr-Mo co-substituted CaMnO3 ceramics were prepared by the conventional mixed oxide route. Crystallographic data from X-ray and electron diffraction showed an orthorhombic to tetragonal symmetry change on increasing the Sr content, suggesting that Sr widens the transition temperature in CaMnO3 preventing phase transformation-cracking on cooling after sintering, enabling the fabrication of high density ceramics. Atomically resolved imaging and analysis showed a random distribution of Sr in the A-site of the perovskite structure and revealed a boundary structure of 90° rotational twin boundaries across {101}orthorhombic; the latter are predominant phonon scattering sources to lower the thermal conductivity as suggested by molecular dynamics calculations. The effect of doping on the thermoelectric properties was evaluated. Increasing Sr substitution reduces the Seebeck coefficient but the power factor remains high due to improved densification by Sr substitution. Mo doping generates additional charge carriers due to the presence of Mn3+ in the Mn4+ matrix, reducing electrical resistivity. The major impact of Sr on thermoelectric behaviour is the reduction of the thermal conductivity as shown experimentally and by modelling. Strontium containing ceramics showed thermoelectric figure of merit (ZT) values higher than 0.1 at temperatures above 850 K. Ca0.7Sr0.3Mn0.96Mo0.04O3 ceramics exhibit enhanced properties with S1000K = -180 μV K-1, ρ1000K = 5 × 10-5 Ωm, k1000K = 1.8 W m-1 K-1 and ZT ≈ 0.11 at 1000 K.
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Affiliation(s)
- D Srivastava
- School of Materials , University of Manchester , Manchester , M13 9PL , UK .
| | - F Azough
- School of Materials , University of Manchester , Manchester , M13 9PL , UK .
| | - R Freer
- School of Materials , University of Manchester , Manchester , M13 9PL , UK .
| | - E Combe
- National Institute of Advanced Industrial Science and Technology , Midorigaoka , Ikeda , Osaka 563-8577 , Japan
| | - R Funahashi
- National Institute of Advanced Industrial Science and Technology , Midorigaoka , Ikeda , Osaka 563-8577 , Japan
| | - D M Kepaptsoglou
- SuperSTEM Laboratory , SciTech Daresbury Campus , Daresbury WA4 4AD , UK
| | - Q M Ramasse
- SuperSTEM Laboratory , SciTech Daresbury Campus , Daresbury WA4 4AD , UK
| | - M Molinari
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK .
| | - S R Yeandel
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK .
| | - J D Baran
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK .
| | - S C Parker
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK .
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28
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Skelton JM, Tiana D, Parker SC, Togo A, Tanaka I, Walsh A. Influence of the exchange-correlation functional on the quasi-harmonic lattice dynamics of II-VI semiconductors. J Chem Phys 2015; 143:064710. [PMID: 26277159 DOI: 10.1063/1.4928058] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We perform a systematic comparison of the finite-temperature structure and properties of four bulk semiconductors (PbS, PbTe, ZnS, and ZnTe) predicted by eight popular exchange-correlation functionals from quasi-harmonic lattice-dynamics calculations. The performance of the functionals in reproducing the temperature dependence of a number of material properties, including lattice parameters, thermal-expansion coefficients, bulk moduli, heat capacities, and phonon frequencies, is evaluated quantitatively against available experimental data. We find that the phenomenological over- and under-binding characteristics of the local-density approximation and the PW91 and Perdew-Burke-Enzerhof (PBE) generalised-gradient approximation (GGA) functionals, respectively, are exaggerated at finite temperature, whereas the PBEsol GGA shows good general performance across all four systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) and revTPSS meta-GGAs provide relatively small improvements over PBE, with the latter being better suited to calculating structural and dynamical properties, but both are considerably more computationally demanding than the simpler GGAs. The dispersion-corrected PBE-D2 and PBE-D3 functionals perform well in describing the lattice dynamics of the zinc chalcogenides, whereas the lead chalcogenides appear to be challenging for these functionals. These findings show that quasi-harmonic calculations with a suitable functional can predict finite-temperature structure and properties with useful accuracy, and that this technique can serve as a means of evaluating the performance of new functionals in the future.
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Affiliation(s)
- Jonathan M Skelton
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Davide Tiana
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Atsushi Togo
- Elements Strategy Initiative for Structural Materials, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Isao Tanaka
- Elements Strategy Initiative for Structural Materials, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Aron Walsh
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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29
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Skelton JM, da Silva EL, Crespo-Otero R, Hatcher LE, Raithby PR, Parker SC, Walsh A. Electronic excitations in molecular solids: bridging theory and experiment. Faraday Discuss 2015; 177:181-202. [PMID: 25631401 DOI: 10.1039/c4fd00168k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
As the spatial and temporal resolution accessible to experiment and theory converge, computational chemistry is an increasingly powerful tool for modelling and interpreting spectroscopic data. However, the study of molecular processes, in particular those related to electronic excitations (e.g. photochemistry), frequently pushes quantum-chemical techniques to their limit. The disparity in the level of theory accessible to periodic and molecular calculations presents a significant challenge when modelling molecular crystals, since accurate calculations require a high level of theory to describe the molecular species, but must also take into account the influence of the crystalline environment on their properties. In this article, we briefly review the different classes of quantum-chemical techniques, and present an overview of methods that account for environmental influences with varying levels of approximation. Using a combination of solid-state and molecular calculations, we quantitatively evaluate the performance of implicit-solvent models for the [Ni(Et4dien)(η2-O,ON)(η1-NO2)] linkage-isomer system as a test case. We focus particularly on the accurate reproduction of the energetics of the isomerisation, and on predicting spectroscopic properties to compare with experimental results. This work illustrates how the synergy between periodic and molecular calculations can be exploited for the study of molecular crystals, and forms a basis for the investigation of more challenging phenomena, such as excited-state dynamics, and for further methodological developments.
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Affiliation(s)
- Jonathan M Skelton
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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30
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Nekoueian K, Hotchen CE, Amiri M, Sillanpää M, Nelson GW, Foord JS, Holdway P, Buchard A, Parker SC, Marken F. Interfacial electron-shuttling processes across KolliphorEL monolayer grafted electrodes. ACS Appl Mater Interfaces 2015; 7:15458-15465. [PMID: 26104182 DOI: 10.1021/acsami.5b03654] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Covalently grafted KolliphorEL (a poly(ethylene glycol)-based transporter molecule for hydrophobic water-insoluble drugs; MW, ca. 2486; diameter, ca. 3 nm) at the surface of a glassy-carbon electrode strongly affects the rate of electron transfer for aqueous redox systems such as Fe(CN)6(3-/4-). XPS data confirm monolayer grafting after electrochemical anodization in pure KolliphorEL. On the basis of voltammetry and impedance measurements, the charge transfer process for the Fe(CN)6(3-/4-) probe molecule is completely blocked after KolliphorEL grafting and in the absence of a "guest". However, in the presence of low concentrations of suitable ferrocene derivatives as guests, mediated electron transfer across the monolayer via a shuttle mechanism is observed. The resulting amplification of the ferrocene electroanalytical signal is investigated systematically and compared for five ferrocene derivatives. The low-concentration electron shuttle efficiency decreases in the following sequence: (dimethylaminomethyl)ferrocene > n-butyl ferrocene > ferrocene dimethanol > ferroceneacetonitrile > ferroceneacetic acid.
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Affiliation(s)
- Khadijeh Nekoueian
- †Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom
- ‡Department of Chemistry, University of Mohaghegh Ardabili, Ardabil 56199-11367, Iran
- §Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland
| | | | - Mandana Amiri
- ‡Department of Chemistry, University of Mohaghegh Ardabili, Ardabil 56199-11367, Iran
| | - Mika Sillanpää
- §Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland
| | - Geoffrey W Nelson
- ∥Imperial College London, Department of Materials, Royal School of Mines, Exhibition Road, London SW7 2AZ, United Kingdom
| | - John S Foord
- ⊥Chemistry Research Laboratories, Oxford University, South Parks Road, Oxford OX1 3TA, United Kingdom
| | - Philip Holdway
- #Department of Materials, Oxford University, Begbroke Science Park, Begbroke Hill, Oxford OX5 1PF, United Kingdom
| | - Antoine Buchard
- †Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom
| | - Stephen C Parker
- †Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom
| | - Frank Marken
- †Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom
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31
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Brincat NA, Parker SC, Molinari M, Allen GC, Storr MT. Density functional theory investigation of the layered uranium oxides U3O8 and U2O5. Dalton Trans 2015; 44:2613-22. [DOI: 10.1039/c4dt02493a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New predictions of structural, electronic and mechanical properties of layered uranium oxides using DFT + U calculations.
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32
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Zhou Q, Zhu R, Parker SC, Zhu J, He H, Molinari M. Modelling the effects of surfactant loading level on the sorption of organic contaminants on organoclays. RSC Adv 2015. [DOI: 10.1039/c5ra05998d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Organoclays can effectively uptake organic contaminants (OCs) from water media, but the sorption mechanisms are not fully established yet, because of the lack of recognition of interlayer structure of organoclays.
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Affiliation(s)
- Qing Zhou
- Key Laboratory of Mineralogy and Metallogeny
- Guangzhou Institute of Geochemistry
- Chinese Academy of Sciences
- Guangzhou 510640
- China
| | - Runliang Zhu
- Key Laboratory of Mineralogy and Metallogeny
- Guangzhou Institute of Geochemistry
- Chinese Academy of Sciences
- Guangzhou 510640
- China
| | | | - Jianxi Zhu
- Key Laboratory of Mineralogy and Metallogeny
- Guangzhou Institute of Geochemistry
- Chinese Academy of Sciences
- Guangzhou 510640
- China
| | - Hongping He
- Key Laboratory of Mineralogy and Metallogeny
- Guangzhou Institute of Geochemistry
- Chinese Academy of Sciences
- Guangzhou 510640
- China
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33
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Skelton JM, Crespo-Otero R, Hatcher LE, Parker SC, Raithby PR, Walsh A. Energetics, thermal isomerisation and photochemistry of the linkage-isomer system [Ni(Et4dien)(η2-O,ON)(η1-NO2)]. CrystEngComm 2015. [DOI: 10.1039/c4ce01411a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isomerisation of an NO2 ligand coordinated to Ni in a molecular crystal is explored using a range of quantum chemical techniques.
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Affiliation(s)
| | | | | | | | | | - Aron Walsh
- Department of Chemistry
- University of Bath
- Bath, UK
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34
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Abstract
Architectural constructs are engineered to impart desirable mechanical properties facilitating bridges spanning a thousand meters and buildings nearly 1 km in height. However, do the same 'engineering-rules' translate to the nanoscale, where the architectural features are less than 0.0001 mm in size? Here, we calculate the mechanical properties of a porous ceramic functional material, ceria, as a function of its nanoarchitecture using molecular dynamics simulation and predict its yield strength to be almost two orders of magnitude higher than the parent bulk material. In particular, we generate models of nanoporous ceria with either a hexagonal or cubic array of one-dimensional pores and simulate their responses to mechanical load. We find that the mechanical properties are critically dependent upon the orientation between the crystal structure (symmetry, direction) and the pore structure (symmetry, direction).
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Affiliation(s)
- Thi X T Sayle
- School of Physical Sciences, University of Kent, Canterbury, CT2 7NZ, UK.
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35
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Brincat NA, Parker SC, Molinari M, Allen GC, Storr MT. Ab Initio Investigation of the UO3 Polymorphs: Structural Properties and Thermodynamic Stability. Inorg Chem 2014; 53:12253-64. [DOI: 10.1021/ic500791m] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Nicholas A. Brincat
- Department
of Chemistry, University of Bath, Claverton Down, Bath, Avon, BA2 7AY, United Kingdom
| | - Stephen C. Parker
- Department
of Chemistry, University of Bath, Claverton Down, Bath, Avon, BA2 7AY, United Kingdom
| | - Marco Molinari
- Department
of Chemistry, University of Bath, Claverton Down, Bath, Avon, BA2 7AY, United Kingdom
| | - Geoffrey C. Allen
- Interface
Analysis Centre, University of Bristol, Bristol, BS2 8BS, United Kingdom
| | - Mark T. Storr
- AWE, Aldermaston, Reading, Berkshire, RG7 4PR, United Kingdom
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36
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Affiliation(s)
- Yuri G. Andreev
- School
of Chemistry, University of St Andrews, St Andrews KY16 9ST, U.K
| | - Pooja M. Panchmatia
- School
of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH, U.K
| | - Zheng Liu
- School
of Chemistry, University of St Andrews, St Andrews KY16 9ST, U.K
| | | | - M. Saiful Islam
- Department
of Chemistry, University of Bath, Bath BA2 7AY, U.K
| | - Peter G. Bruce
- School
of Chemistry, University of St Andrews, St Andrews KY16 9ST, U.K
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37
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Tompsett DA, Parker SC, Islam MS. Rutile (β-)MnO2 Surfaces and Vacancy Formation for High Electrochemical and Catalytic Performance. J Am Chem Soc 2014; 136:1418-26. [DOI: 10.1021/ja4092962] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - M. Saiful Islam
- Department
of Chemistry, University of Bath, Bath BA2 7AY, U.K
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38
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Whiteside A, Fisher CAJ, Parker SC, Saiful Islam M. Particle shapes and surface structures of olivine NaFePO4 in comparison to LiFePO4. Phys Chem Chem Phys 2014; 16:21788-94. [DOI: 10.1039/c4cp02356k] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomistic simulations of NaFePO4 indicate a variety of (nano)particle morphologies can be achieved by tuning surface stabilities, which are compared to those of LiFePO4.
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Affiliation(s)
| | - Craig A. J. Fisher
- Nanostructures Research Laboratory
- Japan Fine Ceramics Center
- Nagoya 456-8587, Japan
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39
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Zhu R, Molinari M, Shapley TV, Parker SC. Modeling the Interaction of Nanoparticles with Mineral Surfaces: Adsorbed C60 on Pyrophyllite. J Phys Chem A 2013; 117:6602-11. [DOI: 10.1021/jp402835v] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Runliang Zhu
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Marco Molinari
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Thomas V. Shapley
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Stephen C. Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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40
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Sayle TXT, Molinari M, Das S, Bhatta UM, Möbus G, Parker SC, Seal S, Sayle DC. Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles. Nanoscale 2013; 5:6063-6073. [PMID: 23719690 DOI: 10.1039/c3nr00917c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Nanomaterials, with potential application as bio-medicinal agents, exploit the chemical properties of a solid, with the ability to be transported (like a molecule) to a variety of bodily compartments. However, the chemical environment can change significantly the structure and hence properties of a nanomaterial. Accordingly, its surface reactivity is critically dependent upon the nature of the (biological) environment in which it resides. Here, we use Molecular Dynamics (MD) simulation, Density Functional Theory (DFT) and aberration corrected TEM to predict and rationalise differences in structure and hence surface reactivity of ceria nanoparticles in different environments. In particular we calculate reactivity 'fingerprints' for unreduced and reduced ceria nanoparticles immersed in water and in vacuum. Our simulations predict higher activities of ceria nanoparticles, towards oxygen release, when immersed in water because the water quenches the coordinative unsaturation of surface ions. Conversely, in vacuum, surface ions relax into the body of the nanoparticle to relieve coordinative unsaturation, which increases the energy barriers associated with oxygen release. Our simulations also reveal that reduced ceria nanoparticles are more active towards surface oxygen release compared to unreduced nanoceria. In parallel, experiment is used to explore the activities of ceria nanoparticles that have suffered a change in environment. In particular, we compare the ability of ceria nanoparticles, in an aqueous environment, to scavenge superoxide radicals compared to the same batch of nanoparticles, which have first been dried and then rehydrated. The latter show a distinct reduction in activity, which we correlate to a change in the redox chemistry associated with moving between different environments. The reactivity of ceria nanoparticles is therefore not only environment dependent, but is also influenced by the transport pathway or history required to reach the particular environment in which its reactivity is to be exploited.
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Affiliation(s)
- Thi X T Sayle
- Department of Engineering and Applied Science, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, UK.
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41
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Abstract
A Monte Carlo Exchange technique is used to study the thermodynamic properties of MgO-MnO nanoparticles ranging in size from 1728 to 21,952 ions. The solubility of Mg(2+) is much greater in MnO than the reverse, reflecting the difference in size between the two cations. The solubility, for a given temperature, diminishes with nanoparticle size. As the Mn concentration is progressively increased the Mn(2+) ions occupy the corners, edges and then surface sites of the nanoparticle before entering subsurface layers. We do not observe any pronounced ordering of the cations within the body of the nanoparticles themselves. The enthalpies of forming ternary nanoparticles from particles of MgO and MnO of the same size vary with the size of the nanoparticle and become more positive for a given concentration as the particle size increases. Free energies of mixing of the two end-member nanoparticles have been determined using the semigrand ensemble. The consolute temperature (the temperature above which there is complete miscibility) increases non-linearly with the size of the nanoparticle by approximately 70% over the size range considered.
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42
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Bristow JK, Parker SC, A. Catlow CR, Woodley SM, Walsh A. Microscopic origin of the optical processes in blue sapphire. Chem Commun (Camb) 2013; 49:5259-61. [DOI: 10.1039/c3cc41506f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Bhatta UM, Ross IM, Sayle TXT, Sayle DC, Parker SC, Reid D, Seal S, Kumar A, Möbus G. Cationic surface reconstructions on cerium oxide nanocrystals: an aberration-corrected HRTEM study. ACS Nano 2012; 6:421-430. [PMID: 22148265 DOI: 10.1021/nn2037576] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Instabilities of nanoscale ceria surface facets are examined on the atomic level. The electron beam and its induced atom migration are proposed as a readily available probe to emulate and quantify functional surface activity, which is crucial for, for example, catalytic performance. In situ phase contrast high-resolution transmission electron microscopy with spherical aberration correction is shown to be the ideal tool to analyze cationic reconstruction. Hydrothermally prepared ceria nanoparticles with particularly enhanced {100} surface exposure are explored. Experimental analysis of cationic reconstruction is supported by molecular dynamics simulations where the Madelung energy is shown to be directly related to the binding energy, which enables one to generate a visual representation of the distribution of "reactive" surface oxygen.
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Affiliation(s)
- Umananda M Bhatta
- Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, UK
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44
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Zhu R, Chen W, Shapley TV, Molinari M, Ge F, Parker SC. Sorptive characteristics of organomontmorillonite toward organic compounds: a combined LFERs and molecular dynamics simulation study. Environ Sci Technol 2011; 45:6504-6510. [PMID: 21721563 DOI: 10.1021/es200211r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Linear free energy relationships (LFER) combined with molecular dynamics (MD) simulations were used to investigate the sorptive characteristics of organic compounds (OCs) on cetyltrimethylammonium (CTMA) intercalated montmorillonite (CTMA-Mont). The LFER for OCs sorption on CTMA-Mont, log K(oc) = (1.45 ± 0.20)E - (0.37 ± 0.15)S + (0.56 ± 0.15)A - (1.75 ± 0.25)B + (2.50 ± 0.45)V + (0.19 ± 0.35), was obtained by a multiple linear regression of the sorption coefficients of the OCs against their solvation descriptors. In comparison to water, CTMA-Mont is more polarizable, less polar and cohesive, and has stronger H-bond acceptor and weaker H-bond donor capacities. Using the above equation we calculated that vV and eE were the dominant solvation terms contributing to the sorption for all the OCs. MD simulations provided atomic-level insight into the interlayer structure of CTMA-Mont. Phenol molecules were shown to be sorbed into the nanosized aggregates formed by CTMA alkyl chains. The hydrophobic environment within the aggregates is responsible for the sorbent's more polarizable, less polar and cohesive characteristics. CTMA-Mont has strong H-bond acceptor and weak H-bond donor capacities as oxygen atoms on the siloxane surface act as H-bond acceptors for both water and OC molecules. With the combination of the results of the two methods, we can provide new insights for understanding the sorptive characteristics of organomontmorillonite.
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Affiliation(s)
- Runliang Zhu
- Department of Environmental Science and Engineering, Xiangtan University, Xiangtan, China
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45
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Cummings CY, Wadhawan JD, Nakabayashi T, Haga MA, Rassaei L, Dale SE, Bending S, Pumera M, Parker SC, Marken F. Electron hopping rate measurements in ITO junctions: Charge diffusion in a layer-by-layer deposited ruthenium(II)-bis(benzimidazolyl)pyridine-phosphonate–TiO2 film. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sayle TXT, Inkson BJ, Karakoti A, Kumar A, Molinari M, Möbus G, Parker SC, Seal S, Sayle DC. Mechanical properties of ceria nanorods and nanochains; the effect of dislocations, grain-boundaries and oriented attachment. Nanoscale 2011; 3:1823-1837. [PMID: 21409243 DOI: 10.1039/c0nr00980f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We predict that the presence of extended defects can reduce the mechanical strength of a ceria nanorod by 70%. Conversely, the pristine material can deform near its theoretical strength limit. Specifically, atomistic models of ceria nanorods have been generated with full microstructure, including: growth direction, morphology, surface roughening (steps, edges, corners), point defects, dislocations and grain-boundaries. The models were then used to calculate the mechanical strength as a function of microstructure. Our simulations reveal that the compressive yield strengths of ceria nanorods, ca. 10 nm in diameter and without extended defects, are 46 and 36 GPa for rods oriented along [211] and [110] respectively, which represents almost 10% of the bulk elastic modulus and are associated with yield strains of about 0.09. Tensile yield strengths were calculated to be about 50% lower with associated yield strains of about 0.06. For both nanorods, plastic deformation was found to proceed via slip in the {001} plane with direction <110>--a primary slip system for crystals with the fluorite structure. Dislocation evolution for the nanorod oriented along [110] was nucleated via a cerium vacancy present at the surface. A nanorod oriented along [321] and comprising twin-grain boundaries with {111} interfacial planes was calculated to have a yield strength of about 10 GPa (compression and tension) with the grain boundary providing the vehicle for plastic deformation, which slipped in the plane of the grain boundary, with an associated <110> slip direction. We also predict, using a combination of atomistic simulation and DFT, that rutile-structured ceria is feasible when the crystal is placed under tension. The mechanical properties of nanochains, comprising individual ceria nanoparticles with oriented attachment and generated using simulated self-assembly, were found to be similar to those of the nanorod with grain-boundary. Images of the atom positions during tension and compression are shown, together with animations, revealing the mechanisms underpinning plastic deformation. For the nanochain, our simulations help further our understanding of how a crystallising ice front can be used to 'sculpt' ceria nanoparticles into nanorods via oriented attachment.
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Affiliation(s)
- Thi X T Sayle
- Dept. Engineering and Applied Science, Cranfield University, Defence Academy of the United Kingdom, Shrivenham, SN6 8LA, UK.
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Spagnoli D, Allen JP, Parker SC. The structure and dynamics of hydrated and hydroxylated magnesium oxide nanoparticles. Langmuir 2011; 27:1821-1829. [PMID: 21226497 DOI: 10.1021/la104190d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An understanding of the structure of water on metal oxide nanoparticles is important due to its involvement in a number of surface processes, such as in the modification of transport near surfaces and the resulting impact on crystal growth and dissolution. However, as direct experimental measurements probing the metal oxide-water interface of nanoparticles are not easily performed, we use atomistic simulations using experimentally derived potential parameters to determine the structure and dynamics of the interface between magnesium oxide nanoparticles and water. We use a simple strategy to generate mineral nanoparticles, which can be applied to any shape, size, or composition. Molecular dynamics simulations were then used to examine the structure of water around the nanoparticles, and highly ordered layers of water were found at the interface. The structure of water is strongly influenced by the crystal structure and morphology of the mineral and the extent of hydroxylation of the surface. Comparison of the structure and dynamics of water around the nanoparticles with their two-dimensional flat surface counterparts revealed that the size, shape, and surface composition also affects properties such as water residence times and coordination number.
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Affiliation(s)
- Dino Spagnoli
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK
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Abstract
Different crystal structures have been proposed as a basis for titanium oxide nanotubes. We have used atomistic simulation techniques to calculate the relative stability of nanotubes with these different crystal structures. Our approach is to use energy minimization, where the total interaction energy is calculated with interatomic potentials based on the Born model of solids. The results reveal nanotubes with the trititanate structure to be the most stable (at unit activity for water). Indeed, nanotubes with the trititanate structure were found to be thermodynamically more favorable than bulk trititanate for nanotube diameters greater than approximately 8 nm. However, the formation of cross-linking bonds between layers of the trititanate structure occurred frequently; this problem was eliminated by replacing two out of three Ti(4+) ions with Ti(3+) ions, although this resulted in a higher energy. Of the structures that do not contain hydrogen, chiral nanotubes made from (101) sheets of anatase are the lowest in energy, suggesting that this is the most likely structure for nanotubes synthesized at low water chemical potential. In general, the stability of the nanotubes increased as the nanotube diameter increased.
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Affiliation(s)
- Judy N Hart
- Department of Chemical Engineering, University of Bath, Bath, United Kingdom
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Allen JP, Greń W, Molinari M, Arrouvel C, Maglia F, Parker SC. Atomistic modelling of adsorption and segregation at inorganic solid interfaces. Molecular Simulation 2009. [DOI: 10.1080/08927020902774570] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Salje EKH, Artacho E, Austen KF, Bruin RP, Calleja M, Chappell HF, Chiang GT, Dove MT, Frame I, Goodwin AL, Kleese van Dam K, Marmier A, Parker SC, Pruneda JM, Todorov IT, Trachenko K, Tyer RP, Walker AM, White TOH. eScience for molecular-scale simulations and the eMinerals project. Philos Trans A Math Phys Eng Sci 2009; 367:967-985. [PMID: 19087935 DOI: 10.1098/rsta.2008.0195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We review the work carried out within the eMinerals project to develop eScience solutions that facilitate a new generation of molecular-scale simulation work. Technological developments include integration of compute and data systems, developing of collaborative frameworks and new researcher-friendly tools for grid job submission, XML data representation, information delivery, metadata harvesting and metadata management. A number of diverse science applications will illustrate how these tools are being used for large parameter-sweep studies, an emerging type of study for which the integration of computing, data and collaboration is essential.
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Affiliation(s)
- E K H Salje
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
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