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Gómez-Toledo M, Arroyo-de Dompablo EM. The SCAN+ U method in the investigation of complex transition metal oxides: a case study on YSr 2Cu 2FeO 7+δ ( δ = 0, 1). Phys Chem Chem Phys 2024; 26:17255-17264. [PMID: 38856309 DOI: 10.1039/d4cp00874j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Assessment of DFT methods is essential to sustain reliability in the computational investigation of complex transition metal oxides. This work evaluates the performance of the strongly constrained and appropriately normed (SCAN) functional and its extended Hubbard-U methodology (SCAN+U) to model the YSr2Cu2FeO7+δ (0 < δ < 1) perovskite-based system. The influence of the individual UCu and UFe Hubbard parameters (0 < U < 4 eV) on the calculated electronic, magnetic and crystal structures of the end members δ = 1 (metallic) and δ = 0 (insulating) is analyzed. The introduction of the U-correction terms enhances the reproduction of the crystal structures, with a UCu value of 1 eV improving the band gap accuracy for the YSr2Cu2FeO7 phase, while maintaining the metallic characteristics of YSr2Cu2FeO8. At a fixed UCu value, the results are almost insensitive to the UFe value used in the calculations. The findings emphasize that for oxides containing several TM ions, the optimal UTM values may differ from those of the simple TM oxides.
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Affiliation(s)
- Marianela Gómez-Toledo
- Departamento de Química Inorgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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2
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Kumar A, Parida P. Iron-arsenide monolayers as an anode material for lithium-ion batteries: a first-principles study. Phys Chem Chem Phys 2024; 26:12060-12069. [PMID: 38586896 DOI: 10.1039/d4cp00062e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
This theoretical investigation delves into the structural, electronic, and electrochemical properties of two hexagonal iron-arsenide monolayers, 1T-FeAs and 1H-FeAs, focusing on their potential as anode materials for lithium-ion batteries. Previous studies have highlighted the ferromagnetic nature of 1T-FeAs at room temperature. Our calculations reveal that both phases exhibit metallic behaviour with spin-polarized electronic band structures. Electrochemical studies show that the 1T-FeAs monolayer has better ionic conductivity for Li ions than the 1H-FeAs phase, attributed to a lower activation barrier of 0.38 eV. This characteristic suggests a faster charge/discharge rate. Both FeAs phases exhibit comparable theoretical capacities (374 mA h g-1), outperforming commercial graphite anodes. The average open-circuit voltage for maximum Li atom adsorption is 0.61 V for 1H-FeAs and 0.44 V for 1T-FeAs. The volume expansion over the maximum adsorption of Li atoms on both phases is also remarkably less than the commercially used anode material such as graphite. Furthermore, the adsorption of Li atoms onto 1H-FeAs induces a remarkable transition from ferromagnetism to anti-ferromagnetism, with minimal impact on the electronic band structure. In contrast, the original state of 1T-FeAs remains unaffected by Li adsorption. To summarize, both 1T-FeAs and 1H-FeAs monolayers have potential as promising anode materials for lithium-ion batteries, offering valuable insights into their electrochemical performance and phase transition behaviour upon Li adsorption.
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Affiliation(s)
- Ajay Kumar
- Department of Physics, Indian Institute of Technology Patna, Bihta, Bihar, India.
| | - Prakash Parida
- Department of Physics, Indian Institute of Technology Patna, Bihta, Bihar, India.
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3
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Yang S, Yu B, Ge R, Liu B, Qi R, Sun L, Zhao Q, Yue F. Optical properties of ferroic Fe 2O(SeO 3) 2 and Fe 2(SeO 3) 3·3H 2O. Phys Chem Chem Phys 2024; 26:3335-3341. [PMID: 38197880 DOI: 10.1039/d3cp04531e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Ferroic compounds Fe2O(SeO3)2 (FSO) and Fe2(SeO3)3·3H2O (FSOH) prepared by the hydrothermal method are characterized and their optical properties are investigated by combining with first-principles calculations. The results show that (i) FSO is antiferromagnetic below ∼110 K and becomes ferromagnetic at elevated temperatures, while FSOH is antiferromagnetic at low temperatures probably due to a change in the spin state from Fe3+ (S = 5/2) to Fe2+ (S = 2); (ii) the optical bandgap is determined to be ∼2.83 eV for FSO and ∼2.15 eV for FSOH, consistent with the theoretical calculation; and (iii) the angle-resolved polarized Raman spectroscopy results of both crystals demonstrate the strong anisotropic light absorption and birefringence effects, and the unconventional symmetricity of some Raman modes is observed, which can be interpreted from the variation of Raman scattering elements. This work can provide not only an understanding of the structure and physical properties of iron selenites, but also a strategy for exploring the anomalous Raman behaviors in anisotropic crystals, facilitating the design and engineering of novel functional devices with low-symmetry ferroic materials.
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Affiliation(s)
- Shuai Yang
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
| | - Bing Yu
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
| | - Rui Ge
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
| | - Beituo Liu
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
| | - Ruijuan Qi
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
| | - Lin Sun
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
| | - Qingbiao Zhao
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, China.
| | - Fangyu Yue
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China.
- Shanghai Center of Brain-inspired Intelligent Materials and Devices, East China Normal University, Shanghai 200241, China
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4
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Jin R, Zhao S, Xiao H. Ab Initio Molecular Dynamics Study of Electron Excitation Effects on UO 2 and U 3Si. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6911. [PMID: 37959506 PMCID: PMC10647829 DOI: 10.3390/ma16216911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/16/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023]
Abstract
In this study, an ab initio molecular dynamics method is employed to investigate how the microstructures of UO2 and U3Si evolve under electron excitation. It is found that the U3Si is more resistant to electron excitation than UO2 at room temperature. UO2 undergoes a crystalline-to-amorphous structural transition with an electronic excitation concentration of 3.6%, whereas U3Si maintains a crystalline structure until an electronic excitation concentration reaches up to 6%. Such discrepancy is mainly due to their different electronic structures. For insulator UO2, once valence U 5f electrons receive enough energy, they are excited to the conduction bands, which induces charge redistribution. Anion disordering is then driven by cation disordering, eventually resulting in structural amorphization. As for metallic U3Si, the U 5f electrons are relatively more difficult to excite, and the electron excitation leads to cation disordering, which eventually drives the crystalline-to-amorphous phase transition. This study reveals that U3Si is more resistant to electron excitation than UO2 under an irradiation environment, which may advance the understanding of related experimental and theoretical investigations to design radiation-resistant nuclear fuel uranium materials.
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Affiliation(s)
| | | | - Haiyan Xiao
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, China; (R.J.); (S.Z.)
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5
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Xiong T, Chen Y, Qiu R, Yuan H. Excellent 5f-electron magnet of actinide atom decorated gh-C 3N 4 monolayer. Phys Chem Chem Phys 2023; 25:28020-28033. [PMID: 37823441 DOI: 10.1039/d3cp02954a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Atomic functionality of two-dimensional (2D) materials, typically with a controllable doping route for offering regular atomic arrangement as well as excellent magnetism, is crucial for both fundamental studies and spintronic applications. Here, the adsorptions of the 5f-electron actinide series (An = Ac-Am) on porous graphene-like carbon-nitride (gh-C3N4) layers are explored to determine their structural stabilities, electronic nature and magnetic properties using the combination of density functional theory (DFT) calculations, ab initio molecular dynamics (AIMD), Monte Carlo (MC) simulations and chemical bonding analyses. Our investigations reveal that each An atom can be individually adsorbed at the vacancy site of gh-C3N4 sheet with high energetic, thermal and dynamical stabilities, which are rooted in the major interactions of ionic An-N bonding as well as the minor interactions of covalent bonding of An-5f6d states with N-2s2p states. The delocalization of a very few 5f electrons is dependent on whether they occupy the suborbitals that are matching and conducive to hybridize with the ligand orbitals forming the 5f-2s2p covalent bonds. We propose that the Ruderman-Kittel-Kasuya-Yosida (RKKY) mechanism plays a determining role for the inter-atomic 5f-5f magnetic exchange via the 6d electrons as the conduction electrons. Large magnetic moment and magnetic anisotropy energy (MAE) from the localized 5f electrons, together with the metallic characteristics owing to the delocalized 6d electrons, render these An-based 2D materials excellent metallic magnets, especially for the U@gh-C3N4 system with the modest magnetic moment of 0.6 μB, large MAE of 53 meV and high Curie temperature (TC) of 538 K.
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Affiliation(s)
- Tao Xiong
- School of Physical Science and Technology, Southwest University, Chongqing, 400715, China.
| | - Yaqing Chen
- School of Physical Science and Technology, Southwest University, Chongqing, 400715, China.
| | - Ruizhi Qiu
- Institute of Materials, China Academy of Engineering Physics, Mianyang, Sichuan, 621907, China.
| | - Hongkuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing, 400715, China.
- Chongqing Key Laboratory of Micro&Nano Structure Optoelectronics, Southwest University, Chongqing, 400715, China
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6
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Gómez-Toledo M, López-Paz SA, García-Martín S, Arroyo-de Dompablo ME. Metal-to-Insulating Transition in the Perovskite System YSr 2Cu 2FeO 8-δ (0 < δ < 1) Modeled by DFT Methods. Inorg Chem 2023; 62:3445-3456. [PMID: 36787462 PMCID: PMC9976288 DOI: 10.1021/acs.inorgchem.2c03475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Progress in the design of functional perovskite oxides relies on advances in density functional theory (DFT) methods to efficiently and effectively model complex systems composed of several transition-metal ions. This work reports the application of DFT methods to investigate the electronic structure of the YSr2Cu2FeO8-δ (0 < δ < 1) family in which the insulating, metal, or superconducting behaviors and even anion conductivity can be tuned by modifying the oxygen content. In particular, we assess the performance of the generalized gradient approximation (GGA), its Hubbard-U correction (GGA + U), and the strongly constrained and appropriately normed (SCAN) to model the metallic (idealized YSr2Cu2FeO8) and insulating (idealized YSr2Cu2FeO7) phases of the system. The analysis of the DFT results is supported by DC resistivity measurements that denote the metal character of the synthesized YSr2Cu2FeO7.86 and the semiconducting character of YSr2Cu2FeO7.08 prepared under reducing conditions. In addition, the band gap of YSr2Cu2FeO7.08, in the range of 0.73-1.2 eV, has been extracted from diffuse reflectance spectroscopy (DRS). While the three methodologies (GGA, GGA + U, SCAN) permit the reproduction of the crystal structures of the synthetized oxides (determined here in the case of YSr2Cu2FeO7.08 by neutron powder diffraction (NPD)), the SCAN emerges as the only one capable to predict the basic electronic and magnetic properties across the YSr2Cu2FeO8-δ (0 < δ < 1) series. The picture that emerges for the metal (δ = 0) to insulating (δ = 1) transition is the one in which oxygen vacancies contribute electrons to the filling of the Cu/Fe-3dx2-y2 states of the conduction band. These results validate the SCAN functional for future DFT investigations of complex functional oxides that combine several transition metals.
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Affiliation(s)
- Marianela Gómez-Toledo
- Departamento
de Química Inorgánica, Universidad
Complutense de Madrid, 28040 Madrid, Spain
| | - Sara A. López-Paz
- Departamento
de Química Inorgánica, Universidad
Complutense de Madrid, 28040 Madrid, Spain,Department
of Quantum Matter Physics, University of
Geneva, CH-1211 Geneva, Switzerland
| | - Susana García-Martín
- Departamento
de Química Inorgánica, Universidad
Complutense de Madrid, 28040 Madrid, Spain
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7
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Hong S, Abbas HG, Jang K, Patra KK, Kim B, Choi BU, Song H, Lee KS, Choi PP, Ringe S, Oh J. Tuning the C 1 /C 2 Selectivity of Electrochemical CO 2 Reduction on Cu-CeO 2 Nanorods by Oxidation State Control. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208996. [PMID: 36470580 DOI: 10.1002/adma.202208996] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/19/2022] [Indexed: 06/17/2023]
Abstract
Ceria (CeO2 ) is one of the most extensively used rare earth oxides. Recently, it has been used as a support material for metal catalysts for electrochemical energy conversion. However, to date, the nature of metal/CeO2 interfaces and their impact on electrochemical processes remains unclear. Here, a Cu-CeO2 nanorod electrochemical CO2 reduction catalyst is presented. Using operando analysis and computational techniques, it is found that, on the application of a reductive electrochemical potential, Cu undergoes an abrupt change in solubility in the ceria matrix converting from less stable randomly dissolved single atomic Cu2+ ions to (Cu0 ,Cu1+ ) nanoclusters. Unlike single atomic Cu, which produces C1 products as the main product during electrochemical CO2 reduction, the coexistence of (Cu0 ,Cu1+ ) clusters lowers the energy barrier for C-C coupling and enables the selective production of C2+ hydrocarbons. As a result, the coexistence of (Cu0 ,Cu1+ ) in the clusters at the Cu-ceria interface results in a C2+ partial current density/unit Cu weight 27 times that of a corresponding Cu-carbon catalyst under the same conditions.
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Affiliation(s)
- Seungwon Hong
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hafiz Ghulam Abbas
- Department of Chemistry, Korea University, Seoul, 02841, Republic of Korea
| | - Kyuseon Jang
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Kshirodra Kumar Patra
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Beomil Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Byeong-Uk Choi
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hakhyeon Song
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Kug-Seung Lee
- Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Pyuck-Pa Choi
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Stefan Ringe
- Department of Chemistry, Korea University, Seoul, 02841, Republic of Korea
| | - Jihun Oh
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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8
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Williams NJ, Seymour ID, Fraggedakis D, Skinner SJ. Electric Fields and Charge Separation for Solid Oxide Fuel Cell Electrodes. NANO LETTERS 2022; 22:7515-7521. [PMID: 36067488 PMCID: PMC9523703 DOI: 10.1021/acs.nanolett.2c02468] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Activation losses at solid oxide fuel cell (SOFC) electrodes have been widely attributed to charge transfer at the electrode surface. The electrostatic nature of electrode-gas interactions allows us to study these phenomena by simulating an electric field across the electrode-gas interface, where we are able to describe the activation overpotential using density functional theory (DFT). The electrostatic responses to the electric field are used to approximate the behavior of an electrode under electrical bias and have found a correlation with experimental data for three different reduction reactions at mixed ionic-electronic conducting (MIEC) electrode surfaces (H2O and CO2 on CeO2; O2 on LaFeO3). In this work, we demonstrate the importance of decoupled ion-electron transfer and charged adsorbates on the performance of electrodes under nonequilibrium conditions. Finally, our findings on MIEC-gas interactions have potential implications in the fields of energy storage and catalysis.
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Affiliation(s)
- Nicholas J. Williams
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - Ieuan D. Seymour
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Dimitrios Fraggedakis
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
| | - Stephen J. Skinner
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
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9
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Kaur A, Singh D, Das A, Kandasami A, Chen CL, Mishra IB, Ahuja R. Spin and valence variation in Cobalt doped Barium Strontium Titanate Ceramics. Phys Chem Chem Phys 2022; 24:19865-19881. [DOI: 10.1039/d2cp01561g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the present decade, owing to half-metallic ferromagnetism, controlled 3d transition metal-doping based defect engineering in oxide perovskites brings considerable attention to the the pursuit of spintronics. We aim to...
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10
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Murugesan K, Lingannan G, Ishigaki K, Uwatoko Y, Sekine C, Kawamura Y, JunIchi H, Joseph B, Vajeeston P, Maheswari PK, Awana VPS, Sonachalam A. Pressure Dependence of Superconducting Properties, Pinning Mechanism, and Crystal Structure of the Fe 0.99Mn 0.01Se 0.5Te 0.5 Superconductor. ACS OMEGA 2021; 6:30419-30431. [PMID: 34805672 PMCID: PMC8600531 DOI: 10.1021/acsomega.1c03721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
We have investigated the pressure (P) effect on structural (up to 10 GPa), transport [R(T): up to 10 GPa], and magnetic [(M(T): up to 1 GPa)] properties and analyzed the flux pinning mechanism of the Fe0.99Mn0.01Se0.5Te0.5 superconductor. The maximum superconducting transition temperature (T c) of 22 K with the P coefficient of T c dT c/dP = +2.6 K/GPa up to 3 GPa (dT c/dP = -3.6 K/GPa, 3 ≤ P ≥ 9 GPa) was evidenced from R(T) measurements. The high-pressure diffraction and density functional theory (DFT) calculations reveal structural phase transformation from tetragonal to hexagonal at 5.9 GPa, and a remarkable change in the unit cell volume is observed at ∼3 GPa where the T c starts to decrease, which may be due to the reduction of charge carriers, as evidenced by a reduction in the density of states (DOS) close to the Fermi level. At higher pressures of 7.7 GPa ≤ P ≥ 10.2 GPa, a mixed phase (tetragonal + hexagonal phase) is observed, and the T c completely vanishes at 9 GPa. A significant enhancement in the critical current density (J C) is observed due to the increase of pinning centers induced by external pressure. The field dependence of the critical current density under pressure shows a crossover from the δl pinning mechanism (at 0 GPa) to the δT c pinning mechanism (at 1.2 GPa). The field dependence of the pinning force at ambient condition and under pressure reveals the dense point pinning mechanism of Fe0.99Mn0.01Se0.5Te0.5. Moreover, both upper critical field (H C2) and J C are enhanced significantly by the application of an external P and change over to a high P phase (hexagonal ∼5.9 GPa) faster than a Fe0.99Ni0.01Se0.5Te0.5 (7.7 GPa) superconductor.
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Affiliation(s)
- Kannan Murugesan
- Centre
for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - Govindaraj Lingannan
- Centre
for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - Kento Ishigaki
- Institute
for Solid state Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Yoshiya Uwatoko
- Institute
for Solid state Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Chihiro Sekine
- Muroran
Institute of Technology, Muroran, Hokkaido 050-8585, Japan
| | | | - Hayashi JunIchi
- Muroran
Institute of Technology, Muroran, Hokkaido 050-8585, Japan
| | - Boby Joseph
- Elettra
Sincrotrone Trieste ScPA, Strada Statale 14, km 163.5, Basovizza 34149, Trieste, Italy
| | - Ponniah Vajeeston
- Department
of Chemistry, Centre for Materials Science and Nanotechnology, University of Oslo, Blindern, P.O. Box 11126, 0318 Oslo, Norway
| | | | - V. P. S. Awana
- National
Physical Laboratory (CSIR), Dr. K. S. Krishnan Road, New Delhi 110012, India
| | - Arumugam Sonachalam
- Centre
for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
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Sassi M, Chaka AM, Rosso KM. Ab initio thermodynamics reveals the nanocomposite structure of ferrihydrite. Commun Chem 2021; 4:134. [PMID: 36697713 PMCID: PMC9814694 DOI: 10.1038/s42004-021-00562-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023] Open
Abstract
Ferrihydrite is a poorly crystalline iron oxyhydroxide nanomineral that serves a critical role as the most bioavailable form of ferric iron for living systems. However, its atomic structure and composition remain unclear due in part to ambiguities in interpretation of X-ray scattering results. Prevailing models so far have not considered the prospect that at the level of individual nanoparticles multiple X-ray indistinguishable phases could coexist. Using ab initio thermodynamics we show that ferrihydrite is likely a nanocomposite of distinct structure types whose distribution depends on particle size, temperature, and hydration. Nanoparticles of two contrasting single-phase ferrihydrite models of Michel and Manceau are here shown to be thermodynamically equivalent across a wide range of temperature and pressure conditions despite differences in their structural water content. Higher temperature and water pressure favor the formation of the former, while lower temperature and water pressure favor the latter. For aqueous suspensions at ambient conditions, their coexistence is maximal for particle sizes up to 12 nm. The predictions inform and help resolve different observations in various experiments.
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Affiliation(s)
- Michel Sassi
- grid.451303.00000 0001 2218 3491Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 USA
| | - Anne M. Chaka
- grid.451303.00000 0001 2218 3491Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 USA
| | - Kevin M. Rosso
- grid.451303.00000 0001 2218 3491Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 USA
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12
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Liu S, Liu L, Cheng Z, Zhu J, Yu R. Surface Structures of Mn 3O 4 and the Partition of Oxidation States of Mn. J Phys Chem Lett 2021; 12:5675-5681. [PMID: 34114819 DOI: 10.1021/acs.jpclett.1c01422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The Mn(III) ions at Mn3O4 surface are hypothesized to contribute to catalytic activity in oxygen reduction reaction. However, the surface structure and stability of Mn3O4 are far less understood. Here, the atomic structures of the widespread (101) and (001) surfaces of Mn3O4 are determined by combining aberration-corrected transmission electron microscopy and DFT calculations. The surface stabilization mechanisms and the oxidation states of Mn are revealed and correlated to the catalytic activity of the surfaces. The results show that the (101) surface undergoes a subsurface reconstruction, forming a rock-salt-type surface layer. The Mn(III) ions are in the outermost layer of the (001) surface but in the subsurface of the (101) surface. The surface partition of the Mn(III) ions provides a microscopic understanding to the observed higher catalytic activity of the (001) surface relative to the (101) surface and would contribute to further development of novel catalysts based on Mn3O4.
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Affiliation(s)
- Shengsheng Liu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Linhan Liu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Zhiying Cheng
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Jing Zhu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Rong Yu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
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13
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Williams NJ, Seymour ID, Leah RT, Mukerjee S, Selby M, Skinner SJ. Theory of the electrostatic surface potential and intrinsic dipole moments at the mixed ionic electronic conductor (MIEC)-gas interface. Phys Chem Chem Phys 2021; 23:14569-14579. [PMID: 33988196 DOI: 10.1039/d1cp01639c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The local activation overpotential describes the electrostatic potential shift away from equilibrium at an electrode/electrolyte interface. This electrostatic potential is not entirely satisfactory for describing the reaction kinetics of a mixed ionic-electronic conducting (MIEC) solid-oxide cell (SOC) electrode where charge transfer occurs at the electrode-gas interface. Using the theory of the electrostatic potential at the MIEC-gas interface as an electrochemical driving force, charge transfer at the ceria-gas interface has been modelled based on the intrinsic dipole potential of the adsorbate. This model gives a physically meaningful reason for the enhancement in electrochemical activity of a MIEC electrode as the steam and hydrogen pressure is increased in both fuel cell and electrolysis modes. This model was validated against operando XPS data from previous literature to accurately predict the outer work function shift of thin film Sm0.2Ce0.8O1.9 in a H2/H2O atmosphere as a function of overpotential.
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Affiliation(s)
- Nicholas J Williams
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| | - Ieuan D Seymour
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| | - Robert T Leah
- Ceres Power Ltd, Viking House, Foundry Lane, Horsham, RH13 5PX, UK
| | | | - Mark Selby
- Ceres Power Ltd, Viking House, Foundry Lane, Horsham, RH13 5PX, UK
| | - Stephen J Skinner
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
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14
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Development of a magnetic nanohybrid for multifunctional application: From immobile photocatalysis to efficient photoelectrochemical water splitting: A combined experimental and computational study. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112575] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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15
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Carlson RK, Cawkwell MJ, Batista ER, Yang P. Tight-Binding Modeling of Uranium in an Aqueous Environment. J Chem Theory Comput 2020; 16:3073-3083. [DOI: 10.1021/acs.jctc.0c00089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rebecca K. Carlson
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - M. J. Cawkwell
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Enrique R. Batista
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ping Yang
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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16
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Ghosh PS, Arya A. Structural, thermodynamic, electronic and elastic properties of Th 1-xU xO 2 and Th 1-xPu xO 2 mixed oxides. Phys Chem Chem Phys 2020; 22:6406-6417. [PMID: 32149299 DOI: 10.1039/d0cp00220h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural, thermodynamic, electronic, and elastic properties of Th1-xUxO2 and Th1-xPuxO2 mixed oxides (MOX) have been calculated with Hubbard corrected density functional theory (DFT+U) to account for the strong 5f electron correlations. The ideal solid solution is approximated by special quasi-random structures and the U-ramping method is used to account for the presence of metastable states in the self-consistent field solution of the DFT+U approach. The mixing enthalpy (ΔHmix) is positive throughout the composition range of the Th1-xUxO2 MOX, consistent with a simple miscibility gap (at low temperature) phase diagram. The behavior of the Th1-xPuxO2 MOX is more complex, where ΔHmix is positive in the ThO2-rich region and negative in the PuO2-rich region. Electronic structure analysis shows that substitution of Th by U/Pu in ThO2 leads to a reduction of the average Th-O bond lengths, causing distortion in the crystal structure. The distortion in the crystal structure results in an increase in the conduction bandwidth and a reduction of the band-gap in the MOX. Good agreement of our DFT+U calculated elastic properties of ThO2, UO2 and PuO2 compounds with experiments leads to convincing prediction of these properties for Th1-xUxO2 and Th1-xPuxO2 MOX.
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Affiliation(s)
- P S Ghosh
- Glass & Advanced Materials Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
| | - A Arya
- Glass & Advanced Materials Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
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17
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Colossal oxygen vacancy formation at a fluorite-bixbyite interface. Nat Commun 2020; 11:1371. [PMID: 32170073 PMCID: PMC7069997 DOI: 10.1038/s41467-020-15153-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 02/16/2020] [Indexed: 11/13/2022] Open
Abstract
Oxygen vacancies in complex oxides are indispensable for information and energy technologies. There are several means to create oxygen vacancies in bulk materials. However, the use of ionic interfaces to create oxygen vacancies has not been fully explored. Herein, we report an oxide nanobrush architecture designed to create high-density interfacial oxygen vacancies. An atomically well-defined (111) heterointerface between the fluorite CeO2 and the bixbyite Y2O3 is found to induce a charge modulation between Y3+ and Ce4+ ions enabled by the chemical valence mismatch between the two elements. Local structure and chemical analyses, along with theoretical calculations, suggest that more than 10% of oxygen atoms are spontaneously removed without deteriorating the lattice structure. Our fluorite–bixbyite nanobrush provides an excellent platform for the rational design of interfacial oxide architectures to precisely create, control, and transport oxygen vacancies critical for developing ionotronic and memristive devices for advanced energy and neuromorphic computing technologies. Oxygen vacancies can impart interesting properties in complex oxides, but specific architectures designed to create high-density oxygen vacancies are largely unknown. Here the authors report a fluorite-bixbyite nanobrush platform to tune interfacial oxygen and show that an atomically well-defined heterointerface can induce charge modulation.
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18
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Gao H, Liu Y, Hu J, Li X. A first-principles study on the influences of metal species Al, Zr, Mo and Tc on the mechanical properties of U 3Si 2. Phys Chem Chem Phys 2020; 22:1833-1840. [PMID: 31746854 DOI: 10.1039/c9cp03814k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A first-principles approach is employed to study the influences of the metal species Al, Zr, Mo and Tc on the mechanical properties of U3Si2. When the Al, Zr, Mo and Tc atoms diffuse into the vacancy sites, they dissolve into the lattice, as confirmed by the solution energies. It is found that the compounds of U3Si2 with low amounts of Al, Zr, Mo, and Tc in the Si vacancies or Al, Zr, and Mo in the U vacancies can behave in the manner of ductility. However, in the cases where Al, Zr, Mo and Tc occupy the interstitial sites, all the compounds are demonstrated to be brittle. Furthermore, the stress-strain relationship for the U3Si1.9375Mo0.0625 system was calculated, which illustrates the enhanced ductility. The current results indicate that the substitution of Si by carefully selected metal atoms can enhance the performance of U3Si2.
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Affiliation(s)
- Haigen Gao
- School of Mechatronics & Vehicle Engineering, East China Jiaotong University, Nanchang 330013, China.
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19
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Gahlot S, Dappozze F, Singh D, Ahuja R, Cardenas L, Burel L, Amans D, Guillard C, Mishra S. Room-temperature conversion of Cu2−xSe to CuAgSe nanoparticles to enhance the photocatalytic performance of their composites with TiO2. Dalton Trans 2020; 49:3580-3591. [DOI: 10.1039/c9dt04726c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Surfactant-free CuAgSe–TiO2 composites show an improved photocatalysis as compared to Cu2−xSe–TiO2 composites or TiO2 alone.
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Affiliation(s)
- Sweta Gahlot
- Université Claude Bernard Lyon 1
- CNRS
- UMR 5256
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON)
- 69626 Villeurbanne
| | - Frederic Dappozze
- Université Claude Bernard Lyon 1
- CNRS
- UMR 5256
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON)
- 69626 Villeurbanne
| | - Deobrat Singh
- Condensed Matter Theory Group
- Department of Physics and Astronomy
- Uppsala University
- 75120 Uppsala
- Sweden
| | - Rajeev Ahuja
- Condensed Matter Theory Group
- Department of Physics and Astronomy
- Uppsala University
- 75120 Uppsala
- Sweden
| | - Luis Cardenas
- Université Claude Bernard Lyon 1
- CNRS
- UMR 5256
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON)
- 69626 Villeurbanne
| | - Laurence Burel
- Université Claude Bernard Lyon 1
- CNRS
- UMR 5256
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON)
- 69626 Villeurbanne
| | - David Amans
- Université Claude Bernard Lyon 1
- CNRS
- Institut Lumière Matière (ILM)
- 69626 Villeurbanne
- France
| | - Chantal Guillard
- Université Claude Bernard Lyon 1
- CNRS
- UMR 5256
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON)
- 69626 Villeurbanne
| | - Shashank Mishra
- Université Claude Bernard Lyon 1
- CNRS
- UMR 5256
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON)
- 69626 Villeurbanne
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20
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Ghosh PS, Arya A. First-principles study of phase stability, electronic and mechanical properties of plutonium sub-oxides. Phys Chem Chem Phys 2019; 21:16818-16829. [PMID: 31334519 DOI: 10.1039/c9cp01858a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formation energies (ΔHf) of fluorite PuO2, α-Pu2O3 and sub-oxides PuO2-x (0.0 < x < 0.5) are determined from atomic scale simulations based on density functional theory (DFT) employing the generalised gradient approximation (GGA) corrected with an effective Hubbard parameter (Ueff). The variation of structural and electronic properties of PuO2 and α-Pu2O3 is determined while ramping up Ueff from 0 eV to 5 eV (Ueff-ramping method) to treat the presence of metastable magnetic states and to determine the most suitable Ueff value matching the experiments. The GGA+U calculated lattice parameter variation as a function of stoichiometry (a(x)) for PuO2-x shows a positive volume of relaxation and an almost linear variation presented by the relation a(x) = a0- 0.522738x, where a0 is the equilibrium lattice parameter of PuO2. The GGA+U calculated ΔHf values of PuO2-x lie above the tie line connecting the ΔHf of PuO2 and Pu2O3, and with decreasing O/Pu ratio, the stability of the sub-oxides increases. The crystal and electronic structure analysis of the oxygen vacancy in PuO2 shows outward anisotropic relaxation of four Pu atoms around the vacancy site. The electronic charges within the Wigner-Seitz sphere around these Pu atoms show an overall gain of only (0.12-0.22)e per Pu atom, signifying an incomplete localization of charges. Finally, the GGA+U calculated single crystal elastic constant values decrease continuously with decreasing O/Pu ratio from 2.0 to 1.5. The rate of decrease of the average C11 is almost 11-15 times higher compared to the rate of decrease of C12 and C44.
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Affiliation(s)
- P S Ghosh
- Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
| | - A Arya
- Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
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21
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Torres A, Luque FJ, Tortajada J, Arroyo-de Dompablo ME. Analysis of Minerals as Electrode Materials for Ca-based Rechargeable Batteries. Sci Rep 2019; 9:9644. [PMID: 31273248 PMCID: PMC6609692 DOI: 10.1038/s41598-019-46002-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/18/2019] [Indexed: 01/01/2023] Open
Abstract
Rechargeable lithium-ion batteries dominate the consumer electronics and electric vehicle markets. However, concerns on Li availability have prompted the development of alternative high energy density electrochemical energy storage systems. Rechargeable batteries based on a Ca metal anode can exhibit advantages in terms of energy density, safety and cost. The development of rechargeable Ca metal batteries requires the identification of suitable high specific energy cathode materials. This work focuses on Ca-bearing minerals because they represent stable and abundant compounds. Suitable minerals should contain a transition metal able of being reversibly reduced and oxidized, which points to several major classes of silicates and carbonates: olivine (CaFeSiO4; kirschsteinite), pyroxene (CaFe/MnSi2O6; hedenbergite and johannsenite, respectively), garnet (Ca3Fe/Cr2Si3O12; andradite and uvarovite, respectively), amphibole (Ca2Fe5Si8O22(OH)2; ferroactinolite) and double carbonates (CaMn(CO3)2; kutnahorite and CaFe(CO3)2; ankerite). This work discusses their electrode characteristics based on crystal chemistry analysis and density functional theory (DFT) calculations. The results indicate that upon Ca deintercalation, compounds such as pyroxene, garnet and double carbonate minerals could display high theoretical energy densities (ranging from 780 to 1500 Wh/kg) with moderate structural modifications. As a downside, DFT calculations indicate a hampered Ca mobility in their crystal structures. The overall analysis then disregards olivine, garnet, pyroxene, amphibole and double carbonates as structural types for future Ca-cathode materials design.
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Affiliation(s)
- A Torres
- Departamento de Química Inorgánica, Facultad de Cc. Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - F J Luque
- Departamento de Mineralogía y Petrología, Facultad de Geología, Universidad Complutense de Madrid, 28040, Madrid, Spain.,Departamento Geomateriales, Instituto de Geociencias IGEO (CSIC, UCM), 28040, Madrid, Spain
| | - J Tortajada
- Departamento de Química Física, Facultad de Cc. Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - M E Arroyo-de Dompablo
- Departamento de Química Inorgánica, Facultad de Cc. Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
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22
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Lynes O, Austin J, Kerridge A. Ab initio molecular dynamics studies of hydroxide coordination of alkaline earth metals and uranyl. Phys Chem Chem Phys 2019; 21:13809-13820. [PMID: 31210212 DOI: 10.1039/c9cp00142e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ab initio molecular dynamics (AIMD) simulations of the Mg2+, Ca2+, Sr2+ and UO22+ ions in either a pure aqueous environment or an environment containing two hydroxide ions have been carried out at the density functional level of theory, employing the generalised gradient approximation via the PBE exchange-correlation functional. Calculated mean M-O bond lengths in the first solvation shell of the aquo systems compared very well to existing experimental and computational literature, with bond lengths well within values measured previously and coordination numbers in line with previously calculated values. When applied to systems containing additional hydroxide ions, the methodology revealed increased bond lengths in all systems. Proton transfer events (PTEs) were recorded and were found to be most prevalent in the strontium hydroxide systems, likely due to the low charge density of the ion and the consequent lack of hydroxide coordination. For all alkaline earths, intrashell PTEs which occurred outside of the first solvation shell were most prevalent. Only three PTEs were identified in the entire simulation data of the uranium dihydroxide system, indicating the clear impact of the increased charge density of the hexavalent uranium ion on the strength of metal-oxygen bonds in aqueous solution. Broadly, systems containing more charge dense ions were found to exhibit fewer PTEs than those containing ions of lower charge density.
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Affiliation(s)
- Olivia Lynes
- Department of Chemistry, Faraday Building, Lancaster University, Lancaster, LA1 4YB, UK.
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23
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Serrano-Sevillano J, Carlier D, Saracibar A, Lopez del Amo JM, Casas-Cabanas M. DFT-Assisted Solid-State NMR Characterization of Defects in Li2MnO3. Inorg Chem 2019; 58:8347-8356. [DOI: 10.1021/acs.inorgchem.9b00394] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jon Serrano-Sevillano
- CIC energiGUNE, Parque Tecnológico de Álava, C/Albert Einstein 48, 01510 Miñano, Álava Spain
- Physical Chemistry Department, Pharmacy Faculty, Basque Country University, 01006 Vitoria-Gasteiz, Álava Spain
| | - Dany Carlier
- CNRS, Bordeaux INP, ICMCB UMR5026, Université Bordeaux, F-33600 Pessac, France
| | - Amaia Saracibar
- Physical Chemistry Department, Pharmacy Faculty, Basque Country University, 01006 Vitoria-Gasteiz, Álava Spain
| | | | - Montse Casas-Cabanas
- CIC energiGUNE, Parque Tecnológico de Álava, C/Albert Einstein 48, 01510 Miñano, Álava Spain
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Structural, Magnetic and Electronic Properties of 3d Transition-Metal Atoms Adsorbed Monolayer BC 2N: A First-principles Study. MATERIALS 2019; 12:ma12101601. [PMID: 31100791 PMCID: PMC6567297 DOI: 10.3390/ma12101601] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 11/16/2022]
Abstract
Based on the monolayer BC2N structure, the structural, electronic and magnetic properties of 3d transition metal (TM) atoms (V, Cr, Mn, Fe, Co and Ni) adsorbed on the monolayer BC2N, are studied by using the first principle method. The results show that 3d transition metal atoms are stably adsorbed on the monolayer BC2N. The most stable adsorption sites for V, Cr, and Mn atoms are the hollow adsorption site (H) of BC2N, while the other 3d TM atoms (Fe, Co, Ni) are more readily adsorbed above the C atoms (Tc). The majority of TM atoms are chemically adsorbed on BC2N, whereas Cr and Mn atoms are physically adsorbed on BC2N. Except for Ni, most 3d transition metal atoms can induce the monolayer BC2N magnetization, and the spin-charge density indicated that the magnetic moments of the adsorption systems are mainly concentrated on the TM atoms. Moreover, the introduction of TM atoms can modulate the electronic structure of a single layer of BC2N, making it advantageous for spintronic applications, and for the development of magnetic nanostructures.
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25
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First-Principles Study of the Structural Stability and Dynamic Properties of Li2MSiO4 (M = Mn, Co, Ni) Polymorphs. ENERGIES 2019. [DOI: 10.3390/en12020224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In recent years, the scientific community has shown an increasing interest in regards to the investigation of novel materials for the intercalation of lithium atoms, suitable for application as cathodes in the new generations of Li-ion batteries. Within this framework, we have computed the relative structural stability, the electronic structure, the elastic and dynamic properties of Li2MSiO4 compounds (M = Mn, Co, Ni) by means of first-principles calculations based on density functional theory. The so-obtained structural parameters of the examined phases are in agreement with previous reports. The energy differences between different polymorphs are found to be small, and most of these structures are dynamically stable. The band structures and density of states are computed to analyse the electronic properties and characterise the chemical bonding. The single crystal elastic constants are calculated for all the examined modifications, proving their mechanical stability. These Li2MSiO4 materials are found to present a ductile behaviour upon deformation. The diffusion coefficients of Li ions, calculated at room temperature for all the examined modifications, reveal a poor conductivity for this class of materials.
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Hybrid Density Functional Study of Au2Cs2I6, Ag2GeBaS4, Ag2ZnSnS4, and AgCuPO4 for the Intermediate Band Solar Cells. ENERGIES 2018. [DOI: 10.3390/en11123457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present a comprehensive investigation of the structural, electronic, mechanical, and optical properties of four promising candidates, namely Au2Cs2I6, Ag2GeBaS4, Ag2ZnSnS4, and AgCuPO4, for application in photovoltaic devices based on intermediate band (IB) cells. We perform accurate density functional theory calculations by employing the hybrid functional of Heyd, Scuseria, and Erhzerhof (HSE06). Calculations reveal that IBs are present in all proposed compounds at unoccupied states in the range of 0.34–2.19 eV from the Fermi level. The structural and mechanical stability of these four materials are also systematically investigated. Additional peaks are present in the optical spectra of these compounds, as characterised by a broadened energy range and high intensity for light absorption. Our findings, as reported in this work, may provide a substantial breakthrough on the understanding of these materials, and thus help the design of more efficient IB solar devices.
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Li P, Wang W, Gong S, Lv F, Huang H, Luo M, Yang Y, Yang C, Zhou J, Qian C, Wang B, Wang Q, Guo S. Hydrogenated Na 2Ti 3O 7 Epitaxially Grown on Flexible N-Doped Carbon Sponge for Potassium-Ion Batteries. ACS APPLIED MATERIALS & INTERFACES 2018; 10:37974-37980. [PMID: 30207451 DOI: 10.1021/acsami.8b11354] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
With its inherent zig-zag layered structure and open framework, Na2Ti3O7 (NTO) is a promising anode material for potassium-ion batteries (KIBs). However, its poor electronic conductivity caused by large band gap (∼3.7 eV) usually leads to low-performance KIBs. In this work, we synthesize the fluff-like hydrogenated Na2Ti3O7 (HNTO) nanowires grown on N-doped carbon sponge (CS) as a binder-free and current-collector-free flexible anode for KIBs (denoted as HNTO/CS). High-resolution X-ray photoelectron spectroscopy (XPS) and electron spin-resonance spectroscopy (ESR) confirm the existence of Ti-OHs and O vacancies in HNTO. The first-principles calculation discloses that both Ti-OHs and O vacancies are equivalent to n-type doping because they can shift the Fermi level up to the conduction band, thus leading to a higher electronic conductivity and better performance for KIBs. In addition, the N-doped CS can further reinforce the conductivity and avoid the aggregation of HNTO nanowires during cycling. As a result, the as-made HNTO/CS can deliver a capacity of 107.8 mAh g-1 at 100 mA g-1 after 20 cycles, and keep the capacity of 90.9% and 82.5% after 200 and 1555 cycles, respectively, much better than the samples without hydrogenation treatment or N-doped CS and reported KTi xO y-based materials. Our work highlights the importance of hydrogenation treatment and N-doped CS in enhancing the electrochemical property for KIBs.
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28
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Rasukkannu M, Velauthapillai D, Bianchini F, Vajeeston P. Properties of Novel Non-Silicon Materials for Photovoltaic Applications: A First-Principle Insight. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E2006. [PMID: 30336564 PMCID: PMC6212800 DOI: 10.3390/ma11102006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/01/2018] [Accepted: 10/11/2018] [Indexed: 11/17/2022]
Abstract
Due to the low absorption coefficients of crystalline silicon-based solar cells, researchers have focused on non-silicon semiconductors with direct band gaps for the development of novel photovoltaic devices. In this study, we use density functional theory to model the electronic structure of a large database of candidates to identify materials with ideal properties for photovoltaic applications. The first screening is operated at the GGA level to select only materials with a sufficiently small direct band gap. We extracted twenty-seven candidates from an initial population of thousands, exhibiting GGA band gap in the range 0.5⁻1 eV. More accurate calculations using a hybrid functional were performed on this subset. Based on this, we present a detailed first-principle investigation of the four optimal compounds, namely, TlBiS₂, Ba₃BiN, Ag₂BaS₂, and ZrSO. The direct band gap of these materials is between 1.1 and 2.26 eV. In the visible region, the absorption peaks that appear in the optical spectra for these compounds indicate high absorption intensity. Furthermore, we have investigated the structural and mechanical stability of these compounds and calculated electron effective masses. Based on in-depth analysis, we have identified TlBiS₂, Ba₃BiN, Ag₂BaS₂, and ZrSO as very promising candidates for photovoltaic applications.
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Affiliation(s)
- Murugesan Rasukkannu
- Department of Computing, Mathematics and Physics, Western Norway University of Applied Sciences, Inndalsveien 28, 5063 Bergen, Norway.
| | - Dhayalan Velauthapillai
- Department of Computing, Mathematics and Physics, Western Norway University of Applied Sciences, Inndalsveien 28, 5063 Bergen, Norway.
| | - Federico Bianchini
- Department of Chemistry, Center for Materials Science and Nanotechnology, University of Oslo, Box 1033, Blindern, N-0315 Oslo, Norway.
| | - Ponniah Vajeeston
- Department of Chemistry, Center for Materials Science and Nanotechnology, University of Oslo, Box 1033, Blindern, N-0315 Oslo, Norway.
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29
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Njifon IC, Bertolus M, Hayn R, Freyss M. Electronic Structure Investigation of the Bulk Properties of Uranium-Plutonium Mixed Oxides (U, Pu)O 2. Inorg Chem 2018; 57:10974-10983. [PMID: 30106281 DOI: 10.1021/acs.inorgchem.8b01561] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present electronic structure calculations of bulk properties of (U, Pu)O2, in the whole Pu content range for which only very few experimental data are available. We use DFT+U and the vdW-DF functional in order to take into account the strong 5f electron correlations and nonlocal correlations. We investigate structural, elastic, electronic, and energetic properties of (U, Pu)O2 in the approximation of the ideal solid solution as described by the special quasirandom structures (SQS) method. The results on electronic properties highlight the narrowing of the band gap due to the mixing of UO2 and PuO2. Results on the mixing enthalpy are used to describe the phase stability of (U, Pu)O2 solid solutions, using both SQS configurations and a parametric method. In particular, the issue of an ideal solid solution on a limited supercell size is discussed.
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Affiliation(s)
| | - Marjorie Bertolus
- CEA, DEN, DEC , Centre de Cadarache , 13108 Saint-Paul-Lez-Durance , France
| | - Roland Hayn
- IM2NP , Aix-Marseille Université , Campus Scientifique Saint-Jerôme, case 142 , 13397 Marseille Cedex 20 , France
| | - Michel Freyss
- CEA, DEN, DEC , Centre de Cadarache , 13108 Saint-Paul-Lez-Durance , France
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30
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Navarrete-López AM, Rivera-Almazo M, Garza J, Vargas R. Importance of one-parameter hybrid exchange-correlation functionals in band gaps of transition metal and metalloid oxides. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2222-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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31
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Arroyo-de Dompablo ME, Krich C, Nava-Avendaño J, Palacín MR, Bardé F. In quest of cathode materials for Ca ion batteries: the CaMO3 perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni). Phys Chem Chem Phys 2018; 18:19966-72. [PMID: 27398629 DOI: 10.1039/c6cp03381d] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Basic electrochemical characteristics of CaMO3 perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni) as cathode materials for Ca ion batteries are investigated using first principles calculations at the Density Functional Theory level (DFT). Calculations have been performed within the Generalized Gradient Approximation (GGA) and GGA+U methodologies, and considering cubic and orthorhombic perovskite structures for CaxMO3 (x = 0, 0.25, 0.5, 0.75 and 1). The analysis of the calculated voltage-composition profile and volume variations identifies CaMoO3 as the most promising perovskite compound. It combines good electronic conductivity, moderate crystal structure modifications, and activity in the 2-3 V region with several intermediate CaxMoO3 phases. However, we found too large barriers for Ca diffusion (around 2 eV) which are inherent to the perovskite structure. The CaMoO3 perovskite was synthesized, characterized and electrochemically tested, and results confirmed the predicted trends.
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Affiliation(s)
- M E Arroyo-de Dompablo
- Malta Consolider Team, Departamento de Química Inorgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - C Krich
- Toyota Motor Europe, Research & Development 3, Advanced Technology 1, Technical Centre, Hoge Wei 33 B, B-1930 Zaventem, Belgium
| | - J Nava-Avendaño
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) Campus UAB, E-08193 Bellaterra, Catalonia, Spain
| | - M R Palacín
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) Campus UAB, E-08193 Bellaterra, Catalonia, Spain
| | - F Bardé
- Toyota Motor Europe, Research & Development 3, Advanced Technology 1, Technical Centre, Hoge Wei 33 B, B-1930 Zaventem, Belgium
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Serrano-Sevillano J, Reynaud M, Saracibar A, Altantzis T, Bals S, van Tendeloo G, Casas-Cabanas M. Enhanced electrochemical performance of Li-rich cathode materials through microstructural control. Phys Chem Chem Phys 2018; 20:23112-23122. [DOI: 10.1039/c8cp04181d] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural defects are used as a design opportunity to prepare better battery materials: limiting capacity and voltage fadings in Li2MnO3.
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Affiliation(s)
| | - Marine Reynaud
- CIC energiGUNE, Parque Tecnológico de Álava, C/Albert Einstein 48
- 01510 Miñano
- Spain
| | - Amaia Saracibar
- Physical Chemistry Department, Basque Country University, Pharmacy Faculty
- Vitoria-Gasteiz
- Spain
| | - Thomas Altantzis
- Electron Microscopy for Materials Research (EMAT), University of Antwerp
- 2020
- Antwerp
- Belgium
| | - Sara Bals
- Electron Microscopy for Materials Research (EMAT), University of Antwerp
- 2020
- Antwerp
- Belgium
| | - Gustaaf van Tendeloo
- Electron Microscopy for Materials Research (EMAT), University of Antwerp
- 2020
- Antwerp
- Belgium
| | - Montse Casas-Cabanas
- CIC energiGUNE, Parque Tecnológico de Álava, C/Albert Einstein 48
- 01510 Miñano
- Spain
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33
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Yang Y, Li J, Huang J, Huang J, Zeng J, Zhao J. Polystyrene-template-assisted synthesis of Li3VO4/C/rGO ternary composite with honeycomb-like structure for durable high-rate lithium ion battery anode materials. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.06.108] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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34
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Liang J, Yang X, Xu C, Zhang T, Li J. Catalytic ativities of single-atom catalysts for CO oxidation: Pt 1 /FeO x vs . Fe 1 /FeO x. CHINESE JOURNAL OF CATALYSIS 2017. [DOI: 10.1016/s1872-2067(17)62879-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Jiang J, Li H, Huang J, Li K, Zeng J, Yang Y, Li J, Wang Y, Wang J, Zhao J. Investigation of the Reversible Intercalation/Deintercalation of Al into the Novel Li 3VO 4@C Microsphere Composite Cathode Material for Aluminum-Ion Batteries. ACS APPLIED MATERIALS & INTERFACES 2017; 9:28486-28494. [PMID: 28770985 DOI: 10.1021/acsami.7b07503] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The Li3VO4@C microsphere composite was first reported as a novel cathode material for rechargeable aluminum-ion batteries (AIBs), which manifests the initial discharge capacity of 137 mAh g-1 and and remains at 48 mAh g-1 after 100 cycles with almost 100% Coulombic efficiency. The detailed intercalation mechanism of Al into the orthorhombic Li3VO4 is investigated by ex situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) of Li3VO4@C electrodes and the nuclear magnetic resonance aluminum spectroscopy (27Al NMR) of ionic liquid electrolytes in different discharge/charge states. First-principle calculations are also carried out to investigate the structural change as Al inserts into the framework of Li3VO4. It is revealed that the Al/Li3VO4@C battery goes through electrochemical dissolution and deposition of metallic aluminum in the anode, as well as the insertion and deinsertion of Al3+ cations in the cathode in the meantime. The rechargeable AIBs fabricated in this work are of low cost and high safety, which may make a step forward in the development of novel cathode materials based on the acidic ionic liquid electrolyte system.
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Affiliation(s)
- Jiali Jiang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - He Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Jianxing Huang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Kun Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Jing Zeng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Yang Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Jiaqi Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Yunhui Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Jing Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
| | - Jinbao Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University , No. 422 Siming South Road, Xiamen, Fujian 361005, China
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Li Y, Yang F, Yu Y. LSDA+ U study on the electronic and anti-ferromagnetic properties of Ni-doped CuO and Cu-doped NiO. CHINESE JOURNAL OF CATALYSIS 2017. [DOI: 10.1016/s1872-2067(17)62796-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Rasukkannu M, Velauthapillai D, Vajeeston P. Computational Modeling of Novel Bulk Materials for the Intermediate-Band Solar Cells. ACS OMEGA 2017; 2:1454-1462. [PMID: 31457517 PMCID: PMC6641013 DOI: 10.1021/acsomega.6b00534] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/31/2017] [Indexed: 06/10/2023]
Abstract
Research communities have been studying materials with intermediate bands (IBs) in the middle of the band gap to produce efficient solar cells. Cells based on these materials could reach theoretical efficiencies up to 63.2%. In this comprehensive study, we investigate by means of accurate first-principle calculation the electronic band structure of 2100 novel compounds (bulk materials) to discover whether the IB is present in these materials. Our calculations are based on the density functional theory, using the generalized-gradient approximation for exchange and correlation terms and focusing on the band structure, the density of states, and the electron effective masses of the structures in the database. The IB structures are obtained by adding metallic or semimetallic atoms in the bulk material. By means of these calculations, we have clearly identified a number of compounds that may having high potential to be used as photovoltaic materials. We present here the numerical results for 17 novel IB materials, which could theoretically prove to be suitable for photovoltaic applications.
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Affiliation(s)
- Murugesan Rasukkannu
- Department
of Computing, Mathematics and Physics, Western
Norway University of Applied Sciences, Inndalsveien 28, 5063 Bergen, Norway
| | - Dhayalan Velauthapillai
- Department
of Computing, Mathematics and Physics, Western
Norway University of Applied Sciences, Inndalsveien 28, 5063 Bergen, Norway
| | - Ponniah Vajeeston
- Department
of Chemistry, Center for Materials Science and Nanotechnology, University of Oslo, P.O.
Box 1033, Blindern, N-0315 Oslo, Norway
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38
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Schottky barrier at graphene/metal oxide interfaces: insight from first-principles calculations. Sci Rep 2017; 7:41771. [PMID: 28165485 PMCID: PMC5292957 DOI: 10.1038/srep41771] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/29/2016] [Indexed: 11/18/2022] Open
Abstract
Anode materials play an important role in determining the performance of lithium ion batteries. In experiment, graphene (GR)/metal oxide (MO) composites possess excellent electrochemical properties and are promising anode materials. Here we perform density functional theory calculations to explore the interfacial interaction between GR and MO. Our result reveals generally weak physical interactions between GR and several MOs (including Cu2O, NiO). The Schottky barrier height (SBH) in these metal/semiconductor heterostructures are computed using the macroscopically averaged electrostatic potential method, and the role of interfacial dipole is discussed. The calculated SBHs below 1 eV suggest low contact resistance; thus these GR/MO composites are favorable anode materials for better lithium ion batteries.
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39
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Morales-García Á, He J, Soares AL, Duarte HA. Surfaces and morphologies of covellite (CuS) nanoparticles by means of ab initio atomistic thermodynamics. CrystEngComm 2017. [DOI: 10.1039/c7ce00203c] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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40
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Vajeeston P, Fjellvåg H. First-principles study of structural stability, dynamical and mechanical properties of Li2FeSiO4 polymorphs. RSC Adv 2017. [DOI: 10.1039/c6ra26555c] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Li2FeSiO4 is an important alternative cathode for next generation Li-ion batteries due to its high theoretical capacity (330 mA h g−1).
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Affiliation(s)
- P. Vajeeston
- Center for Materials Sciences and Nanotechnology
- Department of Chemistry
- University of Oslo
- N-0315 Oslo
- Norway
| | - H. Fjellvåg
- Center for Materials Sciences and Nanotechnology
- Department of Chemistry
- University of Oslo
- N-0315 Oslo
- Norway
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41
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Liang JX, Yang XF, Wang A, Zhang T, Li J. Theoretical investigations of non-noble metal single-atom catalysis: Ni1/FeOx for CO oxidation. Catal Sci Technol 2016. [DOI: 10.1039/c6cy00672h] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The single-atom catalyst Ni1/FeOx has a high activity for CO oxidation and the oxygen vacancy on the surface of this catalyst can be created at room temperature.
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Affiliation(s)
- Jin-Xia Liang
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science
- Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology
- Guizhou Education University
- Guiyang 550018
- China
| | - Xiao-Feng Yang
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- China
| | - Aiqin Wang
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- China
| | - Tao Zhang
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- China
| | - Jun Li
- Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education
- Tsinghua University
- Beijing 100084
- China
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42
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Saracibar A, Carrasco J, Saurel D, Galceran M, Acebedo B, Anne H, Lepoitevin M, Rojo T, Casas Cabanas M. Investigation of sodium insertion–extraction in olivine NaxFePO4 (0 ≤ x ≤ 1) using first-principles calculations. Phys Chem Chem Phys 2016; 18:13045-51. [DOI: 10.1039/c6cp00762g] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A molecular level investigation of sodium insertion–extraction in olivine NaxFePO4 as a promising cathode material for sodium-ion batteries.
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Affiliation(s)
- A. Saracibar
- Physical Chemistry Department
- Basque Country University
- Vitoria-Gasteiz
- Spain
| | - J. Carrasco
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
| | - D. Saurel
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
| | - M. Galceran
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
| | - B. Acebedo
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
| | - H. Anne
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
| | - M. Lepoitevin
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
| | - T. Rojo
- CIC-Energigune
- Parque Tecnológico de Alava
- Miñano
- Spain
- Inorganic Chemistry Deparment
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43
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Kvashnina KO, Kvashnin YO, Vegelius JR, Bosak A, Martin PM, Butorin SM. Sensitivity to Actinide Doping of Uranium Compounds by Resonant Inelastic X-ray Scattering at Uranium L3 Edge. Anal Chem 2015; 87:8772-80. [DOI: 10.1021/acs.analchem.5b01699] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kristina O. Kvashnina
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, BP 220, 38043, Grenoble, France
| | - Yaroslav O. Kvashnin
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, BP 220, 38043, Grenoble, France
- Department
of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - Johan R. Vegelius
- Department
of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - Alexei Bosak
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, BP 220, 38043, Grenoble, France
| | | | - Sergei M. Butorin
- Department
of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
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44
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Allen JP, Watson GW. Occupation matrix control of d- and f-electron localisations using DFT + U. Phys Chem Chem Phys 2014; 16:21016-31. [PMID: 24832683 DOI: 10.1039/c4cp01083c] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The use of a density functional theory methodology with on-site corrections (DFT + U) has been repeatedly shown to give an improved description of localised d and f states over those predicted with a standard DFT approach. However, the localisation of electrons also carries with it the problem of metastability, due to the possible occupation of different orbitals and different locations. This study details the use of an occupation matrix control methodology for simulating localised d and f states with a plane-wave DFT + U approach which allows the user to control both the site and orbital localisation. This approach is tested for orbital occupation using octahedral and tetrahedral Ti(iii) and Ce(iii) carbonyl clusters and for orbital and site location using the periodic systems anatase-TiO2 and CeO2. The periodic cells are tested by the addition of an electron and through the formation of a neutral oxygen vacancy (leaving two electrons to localise). These test systems allow the successful study of orbital degeneracies, the presence of metastable states and the importance of controlling the site of localisation within the cell, and it highlights the use an occupation matrix control methodology can have in electronic structure calculations.
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Affiliation(s)
- Jeremy P Allen
- School of Chemistry and CRANN, Trinity College Dublin, Dublin 2, Ireland.
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45
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Dorado B, Freyss M, Amadon B, Bertolus M, Jomard G, Garcia P. Advances in first-principles modelling of point defects in UO2: f electron correlations and the issue of local energy minima. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:333201. [PMID: 23893864 DOI: 10.1088/0953-8984/25/33/333201] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Over the last decade, a significant amount of work has been devoted to point defect behaviour in UO2 using approximations beyond density functional theory (DFT), in particular DFT + U and hybrid functionals for correlated electrons. We review the results of these studies from calculations of bulk UO2 properties to the more recent determination of activation energies for self-diffusion in UO2, as well as a comparison with their experimental counterparts. We also discuss the efficiency of the three known methods developed to circumvent the presence of metastable states, namely occupation matrix control, U-ramping and quasi-annealing.
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Affiliation(s)
- B Dorado
- CEA, DAM, DIF, F-91297 Arpajon, France.
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46
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Aguiar JA, Ramasse QM, Asta M, Browning ND. Investigating the electronic structure of fluorite-structured oxide compounds: comparison of experimental EELS with first principles calculations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:295503. [PMID: 22739407 DOI: 10.1088/0953-8984/24/29/295503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Energy loss spectra from fluorite-structured ZrO(2), CeO(2), and UO(2) compounds are compared with theoretical calculations based on density functional theory (DFT) and its extensions, including the use of Hubbard-U corrections (DFT + U) and hybrid functionals. Electron energy loss spectra (EELS) were obtained from each oxide using a scanning transmission electron microscope (STEM). The same spectra were computed within the framework of the full-potential linear augmented plane-wave (FLAPW) method. The theoretical and experimental EEL spectra are compared quantitatively using non-linear least squares peak fitting and a cross-correlation approach, with the best level of agreement between experiment and theory being obtained using the DFT + U and hybrid computational approaches.
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Affiliation(s)
- J A Aguiar
- Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616, USA.
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47
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Gryaznov D, Heifets E, Kotomin E. The first-principles treatment of the electron-correlation and spin-orbital effects in uranium mononitride nuclear fuels. Phys Chem Chem Phys 2012; 14:4482-90. [PMID: 22362264 DOI: 10.1039/c2cp40297a] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The DFT+U calculations were employed in a detailed study of the strong electron correlation effects in a promising nuclear fuel-uranium mononitride (UN). A simple method for solving the multiple minima problem in DFT+U simulations and insure obtaining the correct ground state is suggested and applied. The crucial role of spin-orbit interactions in reproduction of the U atom total magnetic moment is demonstrated. Basic material properties (the lattice constants, the spin- and total magnetic moments on U atoms, the magnetic ordering, and the density of states) were calculated varying the Hubbard U-parameter. By varying the tetragonal unit cell distortion, the meta-stable states have been carefully identified and analyzed. The difference in the magnetic and structural properties obtained for the meta-stable and ground states is discussed. The optimal effective Hubbard parameter U(eff) = 1.85 eV reproduces correctly the UN anti-ferromagnetic ordering, and only slightly overestimates the experimental total magnetic moment of the U atom and the unit cell volume.
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Affiliation(s)
- Denis Gryaznov
- European Commission, Joint Research Centre, Institute for Transuranim Elements, Karlsruhe, Germany.
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48
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Arroyo-de Dompablo ME, Morales-García A, Taravillo M. DFT+U calculations of crystal lattice, electronic structure, and phase stability under pressure of TiO2 polymorphs. J Chem Phys 2011; 135:054503. [PMID: 21823708 DOI: 10.1063/1.3617244] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
This work investigates crystal lattice, electronic structure, relative stability, and high pressure behavior of TiO(2) polymorphs (anatase, rutile, and columbite) using the density functional theory (DFT) improved by an on-site Coulomb self-interaction potential (DFT+U). For the latter the effect of the U parameter value (0 < U < 10 eV) is analyzed within the local density approximation (LDA+U) and the generalized gradient approximation (GGA+U). Results are compared to those of conventional DFT and Heyd-Scuseria-Ernzehorf screened hybrid functional (HSE06). For the investigation of the individual polymorphs (crystal and electronic structures), the GGA+U/LDA+U method and the HSE06 functional are in better agreement with experiments compared to the conventional GGA or LDA. Within the DFT+U the reproduction of the experimental band-gap of rutile/anatase is achieved with a U value of 10/8 eV, whereas a better description of the crystal and electronic structures is obtained for U < 5 eV. Conventional GGA∕LDA and HSE06 fail to reproduce phase stability at ambient pressure, rendering the anatase form lower in energy than the rutile phase. The LDA+U excessively stabilizes the columbite form. The GGA+U method corrects these deficiencies; U values between 5 and 8 eV are required to get an energetic sequence consistent with experiments (E(rutile) < E(anatase) < E(columbite)). The computed phase stability under pressure within the GGA+U is also consistent with experimental results. The best agreement between experimental and computed transition pressures is reached for U ≈ 5 eV.
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Affiliation(s)
- M E Arroyo-de Dompablo
- Departamento de Química Inorgánica, MALTA Consolider Team, Facultad de CC Químicas, Universidad Complutense de Madrid, Madrid, Spain.
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49
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Inerbaev TM, Seal S, Masunov AE. Density functional study of oxygen vacancy formation and spin density distribution in octahedral ceria nanoparticles. J Mol Model 2010; 16:1617-23. [PMID: 20195666 DOI: 10.1007/s00894-010-0671-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 01/25/2010] [Indexed: 10/19/2022]
Abstract
We report plane wave basis density functional theory (DFT) calculations of the oxygen vacancies formation energy in nanocrystalline CeO2-x in comparison with corresponding results for bulk and (111) CeO2 surface. Effects of strong electronic correlation of Ce4f states are taken into account through the use of an effective on-site Coulomb repulsive interaction within DFT+U approach. Different combinations of exchange-correlation functionals and corresponding U values reported in the literature are tested and the obtained results compared with experimental data. We found that both absolute values and trends in oxygen vacancy formation energy depend on the value of U and associated with degree of localization of Ce4f states. Effect of oxygen vacancy and geometry optimization method on spatial spin distribution in model ceria nanoparticles is also discussed.
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Affiliation(s)
- Talgat M Inerbaev
- NanoScience Technology Center, Department of Mechanical, Material and Aerospace Engineering, University of Central Florida, 12424 Research Parkway, Ste 400, Orlando, FL 32826, USA
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50
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Kang YM, Suh SB, Kim YS. First-Principle Calculation-Assisted Structural Study on the Nanoscale Phase Transition of Si for Li-Ion Secondary Batteries. Inorg Chem 2009; 48:11631-5. [DOI: 10.1021/ic901674s] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yong-Mook Kang
- Division of Advanced Materials Engineering, Kongju National University, 275 Budae-dong, Cheonan, Chungnam, Republic of Korea
| | - Seung-Bum Suh
- Energy Lab, Samsung SDI Co., LTD, 428-5, Gongse-ri, Giheung-eup, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Yang-Soo Kim
- Sunchon Branch, Korea Basic Science Institute, 315 Maegok, Sunchon, Jeonranam-do, Republic of Korea
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