1
|
Kumari S, Mishra RK, Parveen S, Avinashi SK, Hussain A, Kumar S, Banerjee M, Rao J, Kumar R, Gautam RK, Gautam C. Fabrication, structural, and enhanced mechanical behavior of MgO substituted PMMA composites for dental applications. Sci Rep 2024; 14:2128. [PMID: 38267527 PMCID: PMC10808548 DOI: 10.1038/s41598-024-52202-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/16/2024] [Indexed: 01/26/2024] Open
Abstract
The most common denture material used for dentistry is poly-methyl-methacrylate (PMMA). Usually, the polymeric PMMA material has numerous biological, mechanical and cost-effective shortcomings. Hence, to resolve such types of drawbacks, attempts have been made to investigate fillers of the PMMA like alumina (Al2O3), silica (SiO2), zirconia (ZrO2) etc. For the enhancement of the PMMA properties a suitable additive is required for its orthopedic applications. Herein, the main motive of this study was to synthesize a magnesium oxide (MgO) reinforced polymer-based hybrid nano-composites by using heat cure method with superior optical, biological and mechanical characteristics. For the structural and vibrational studies of the composites, XRD and FT-IR were carried out. Herein, the percentage of crystallinity for all the fabricated composites were also calculated and found to be 14.79-30.31. Various physical and optical parameters such as density, band gap, Urbach energy, cutoff energy, cutoff wavelength, steepness parameter, electron-phonon interaction, refractive index, and optical dielectric constant were also studied and their values are found to be in the range of 1.21-1.394 g/cm3, 5.44-5.48 eV, 0.167-0.027 eV, 5.68 eV, 218 nm, 0.156-0.962, 4.273-0.693, 1.937-1.932, and 3.752-3.731 respectively. To evaluate the mechanical properties like compressive strength, flexural strength, and fracture toughness of the composites a Universal Testing Machine (UTM) was used and their values were 60.3 and 101 MPa, 78 and 40.3 MPa, 5.85 and 9.8 MPa-m1/2 respectively. Tribological tests of the composites were also carried out. In order to check the toxicity, MTT assay was also carried out for the PM0 and PM15 [(x)MgO + (100 - x) (C5O2H8)n] (x = 0 and 15) composites. This study provides a comprehensive insight into the structural, physical, optical, and biological features of the fabricated PMMA-MgO composites, highlighting the potential of the PM15 composite with its enhanced density, mechanical strength, and excellent biocompatibility for denture applications.
Collapse
Affiliation(s)
- Savita Kumari
- Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Rajat Kumar Mishra
- Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Shama Parveen
- Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | | | - Ajaz Hussain
- Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Saurabh Kumar
- Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Monisha Banerjee
- Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Jitendra Rao
- Department of Prosthodontics, King George Medical University, Shah Mina Road, Chowk, Lucknow, Uttar Pradesh, 226003, India
| | - Rupesh Kumar
- Department of Mechanical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi, UP, 221005, India
| | - Rakesh Kumar Gautam
- Department of Mechanical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi, UP, 221005, India
| | - Chandkiram Gautam
- Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India.
| |
Collapse
|
2
|
da Silva Alvim R, Borges I, Alves RMB, Capaz RB, Leitão AA. CO adsorption on MgO thin-films: formation and interaction of surface charged defects. Phys Chem Chem Phys 2023; 25:28982-28997. [PMID: 37859503 DOI: 10.1039/d3cp03320a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Two-dimensional (2D) materials formed by thin-films of metal oxides that grow on metal supports are commonly used in heterogeneous catalysis and multilayer electronic devices. Despite extensive research on these systems, the effects of charged defects at supported oxides on surface processes are still not clear. In this work, we perform spin-polarized density-functional theory (DFT) calculations to investigate formation and interaction of charged magnesium and oxygen vacancies, and Al dopants on MgO(001)/Ag(001) surface. The results show a sizable interface compressive effect that decreases the metal work function as electrons are added on the MgO surface with a magnesium vacancy. This surface displays a larger formation energy in a water environment (O-rich condition) even with additional Al-doping. Under these conditions, we found that a polar molecule such as CO is more strongly adsorbed on the low-coordination oxygen sites due to a larger contribution of the channeled electronic transport with the silver interface regardless of the surface charge. Therefore, these findings elucidate how surface intrinsic vacancies can influence or contribute to charge transfer, which allows one to explore more specific reactions at different surface topologies for more efficient catalysts for CO2 conversion.
Collapse
Affiliation(s)
- Raphael da Silva Alvim
- Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo (USP), São Paulo, SP, 05508-900, Brazil.
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG, 36036-330, Brazil
| | - Itamar Borges
- Departamento de Química, Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ, 22290-270, Brazil
| | - Rita Maria Brito Alves
- Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo (USP), São Paulo, SP, 05508-900, Brazil.
| | - Rodrigo B Capaz
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-972, Brazil
- Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, 13083-100, Brazil
| | - Alexandre Amaral Leitão
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG, 36036-330, Brazil
| |
Collapse
|
3
|
Ma R, Sun Y, Ge M, Ma C, Zhang J. Electronic and magnetic properties of charged point defects in monolayer CrI 3. Phys Chem Chem Phys 2023; 25:8809-8815. [PMID: 36916286 DOI: 10.1039/d2cp05657g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The two-dimensional magnetic material CrI3 has gained considerable attention owing to its promising applications in photoelectric and spin-related devices. Recently, various structural defects in CrI3 have been identified; however, the charge states of these defects have been mainly ignored. Here, we report on an investigation of the charged defects in monolayer CrI3, focused on the electronic and magnetic properties of the five most stable point defects using first-principles calculations. For positively charged I vacancies and negatively charged Cr vacancies, a blue- and red-shift of defect states near the Fermi level can be observed because of the atom relaxation. Our results also indicate that, among the five defects, the Cr interstitial defect has the smallest ionization energy of 0.34 eV, which makes its ionization easiest. Furthermore, a 0.2 μB enhancement of the magnetic moment on the nearest Cr atom can be found for the I vacancy and Cr interstitial defect. The investigation contributes to the atomic-scale comparison and understanding of the charged defects of monolayer CrI3.
Collapse
Affiliation(s)
- Rongrong Ma
- School of Physics and Information, Shanxi Normal University, Taiyuan 030031, China.
- Key Laboratory of Spectral Measurement and Analysis of Shanxi Province, Shanxi Normal University, Taiyuan 030031, China
| | - Yun Sun
- School of Physics and Information, Shanxi Normal University, Taiyuan 030031, China.
- Key Laboratory of Spectral Measurement and Analysis of Shanxi Province, Shanxi Normal University, Taiyuan 030031, China
| | - Mei Ge
- School of Physics and Information, Shanxi Normal University, Taiyuan 030031, China.
- Key Laboratory of Spectral Measurement and Analysis of Shanxi Province, Shanxi Normal University, Taiyuan 030031, China
| | - Chenrui Ma
- School of Physics and Information, Shanxi Normal University, Taiyuan 030031, China.
- Key Laboratory of Spectral Measurement and Analysis of Shanxi Province, Shanxi Normal University, Taiyuan 030031, China
| | - Junfeng Zhang
- School of Physics and Information, Shanxi Normal University, Taiyuan 030031, China.
- Key Laboratory of Spectral Measurement and Analysis of Shanxi Province, Shanxi Normal University, Taiyuan 030031, China
| |
Collapse
|
4
|
Bramley GA, Beynon OT, Stishenko PV, Logsdail AJ. The application of QM/MM simulations in heterogeneous catalysis. Phys Chem Chem Phys 2023; 25:6562-6585. [PMID: 36810655 DOI: 10.1039/d2cp04537k] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The QM/MM simulation method is provenly efficient for the simulation of biological systems, where an interplay of extensive environment and delicate local interactions drives a process of interest through a funnel on a complex energy landscape. Recent advances in quantum chemistry and force-field methods present opportunities for the adoption of QM/MM to simulate heterogeneous catalytic processes, and their related systems, where similar intricacies exist on the energy landscape. Herein, the fundamental theoretical considerations for performing QM/MM simulations, and the practical considerations for setting up QM/MM simulations of catalytic systems, are introduced; then, areas of heterogeneous catalysis are explored where QM/MM methods have been most fruitfully applied. The discussion includes simulations performed for adsorption processes in solvent at metallic interfaces, reaction mechanisms within zeolitic systems, nanoparticles, and defect chemistry within ionic solids. We conclude with a perspective on the current state of the field and areas where future opportunities for development and application exist.
Collapse
Affiliation(s)
- Gabriel Adrian Bramley
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, CF10 3AT, UK.
| | - Owain Tomos Beynon
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, CF10 3AT, UK.
| | | | - Andrew James Logsdail
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, CF10 3AT, UK.
| |
Collapse
|
5
|
Zhang X, Zhu L, Hou Q, Guan J, Lu Y, Keal TW, Buckeridge J, Catlow CRA, Sokol AA. Toward a Consistent Prediction of Defect Chemistry in CeO 2. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:207-227. [PMID: 36644213 PMCID: PMC9835833 DOI: 10.1021/acs.chemmater.2c03019] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/25/2022] [Indexed: 05/10/2023]
Abstract
Polarizable shell-model potentials are widely used for atomic-scale modeling of charged defects in solids using the Mott-Littleton approach and hybrid Quantum Mechanical/Molecular Mechanical (QM/MM) embedded-cluster techniques. However, at the pure MM level of theory, the calculated defect energetics may not satisfy the requirement of quantitative predictions and are limited to only certain charged states. Here, we proposed a novel interatomic potential development scheme that unifies the predictions of all relevant charged defects in CeO2 based on the Mott-Littleton approach and QM/MM electronic-structure calculations. The predicted formation energies of oxygen vacancies accompanied by different excess electron localization patterns at the MM level of theory reach the accuracy of density functional theory (DFT) calculations using hybrid functionals. The new potential also accurately reproduces a wide range of physical properties of CeO2, showing excellent agreement with experimental and other computational studies. These findings provide opportunities for accurate large-scale modeling of the partial reduction and nonstoichiometry in CeO2, as well as a prototype for developing robust interatomic potentials for other defective crystals.
Collapse
Affiliation(s)
- Xingfan Zhang
- Kathleen
Lonsdale Materials Chemistry, Department of Chemistry, University College London, LondonWC1H 0AJ, United Kingdom
| | - Lei Zhu
- Kathleen
Lonsdale Materials Chemistry, Department of Chemistry, University College London, LondonWC1H 0AJ, United Kingdom
| | - Qing Hou
- Kathleen
Lonsdale Materials Chemistry, Department of Chemistry, University College London, LondonWC1H 0AJ, United Kingdom
- Institute
of Photonic Chips, University of Shanghai
for Science and Technology, Shanghai200093, China
| | - Jingcheng Guan
- Kathleen
Lonsdale Materials Chemistry, Department of Chemistry, University College London, LondonWC1H 0AJ, United Kingdom
| | - You Lu
- Scientific
Computing Department, STFC Daresbury Laboratory, Warrington, CheshireWA4 4AD, United Kingdom
| | - Thomas W. Keal
- Scientific
Computing Department, STFC Daresbury Laboratory, Warrington, CheshireWA4 4AD, United Kingdom
| | - John Buckeridge
- School
of Engineering, London South Bank University, LondonSE1 OAA, United Kingdom
| | - C. Richard A. Catlow
- Kathleen
Lonsdale Materials Chemistry, Department of Chemistry, University College London, LondonWC1H 0AJ, United Kingdom
- School
of Chemistry, Cardiff University, Park Place, CardiffCF10 1AT, United
Kingdom
| | - Alexey A. Sokol
- Kathleen
Lonsdale Materials Chemistry, Department of Chemistry, University College London, LondonWC1H 0AJ, United Kingdom
| |
Collapse
|
6
|
Lu Y, Zheng F, Lan Q, Schnedler M, Ebert P, Dunin-Borkowski RE. Counting Point Defects at Nanoparticle Surfaces by Electron Holography. NANO LETTERS 2022; 22:6936-6941. [PMID: 36041122 DOI: 10.1021/acs.nanolett.2c01510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metal oxide nanoparticles exhibit outstanding catalytic properties, believed to be related to the presence of oxygen vacancies at the particle's surface. However, little quantitative information is known about concentrations of point defects inside and at surfaces of these nanoparticles, due to the challenges in achieving an atomically resolved experimental access. By employing off-axis electron holography, we demonstrate, using MgO nanoparticles as an example, a methodology that discriminates between mobile charge induced by electron beam irradiation and immobile charge associated with deep traps induced by point defects as well as distinguishes between bulk and surface point defects. Counting the immobile charge provides a quantification of the concentration of F2+ centers induced by oxygen vacancies at the MgO nanocube surfaces.
Collapse
Affiliation(s)
- Yan Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Beijing Key Lab and Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, China
| | - Fengshan Zheng
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Qianqian Lan
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Michael Schnedler
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Philipp Ebert
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| |
Collapse
|
7
|
Ishikawa A, Murase F, Tateyama Y, Otomo J. Favorable Role of the Metal-Support Perimeter Region in Electrochemical NH 3 Synthesis: A Density Functional Theory Study on Ru/BaCeO 3. ACS OMEGA 2022; 7:26107-26115. [PMID: 35936417 PMCID: PMC9352217 DOI: 10.1021/acsomega.2c01222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The catalytic electrochemical synthesis of NH3 on Ru/BaCeO3 was investigated using density functional theory. The competition between NH3 formation and the hydrogen evolution reaction (HER) is a key for a high NH3 formation rate. Our calculations show that H adsorbs more strongly than N2 at the Ru particle moiety, while the adsorption of N2 is stronger than the H adsorption at the Ru/BaCeO3 perimeter, a model for the triple-phase boundary that is proposed to be an active site by experimental studies. This indicates that, while the HER is more favorable at the Ru particle moiety, it should be suppressed at the Ru/BaCeO3 perimeter. We also calculated the Gibbs free energy changes along the NH3 formation and found that the N2H formation, the NHNH2 formation, and the NH3 formation steps have a relatively large Gibbs energy change. Therefore, these are possible candidates for the potential-determining step. The calculated equilibrium potential (U = -0.70 V, vs RHE) is in reasonable agreement with experiments. We also evaluated the reaction energy (ΔE) and the activation barrier (E a) of the N2H formation at several sites. ΔE and E a were high at the Ru particle moiety (ΔE = 1.18 eV and E a = 1.38 eV) but became low (ΔE = 0.32 eV and E a = 1.31 eV) at the Ru/BaCeO3 perimeter. These provide the atomic-scale mechanism how the proton conduction in BaCeO3 assists the electrochemical NH3 synthesis.
Collapse
Affiliation(s)
- Atsushi Ishikawa
- Center
for Green Research on Energy and Environmental Materials (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Elements
Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Fumiya Murase
- Department
of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan
| | - Yoshitaka Tateyama
- Center
for Green Research on Energy and Environmental Materials (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Elements
Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
- International
Center for Materials Nanoarchitectonics (MANA), NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Junichiro Otomo
- Department
of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan
- Department
of Transdisciplinary Science and Engineering, School of Environment
and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550, Japan
| |
Collapse
|
8
|
Pacchioni G, Rahman TS. Defect engineering of oxide surfaces: dream or reality? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:291501. [PMID: 35504272 DOI: 10.1088/1361-648x/ac6c6d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/03/2022] [Indexed: 06/14/2023]
Abstract
In this brief perspective we analyze the present status of the field of defect engineering of oxide surfaces. In particular we discuss the tools and techniques available to generate, identify, quantify, and characterize point defects at oxide surfaces and the main areas where these centers play a role in practical applications.
Collapse
Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 202125, Milano, Italy
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
- Renewable Energy and Chemical Transformation Cluster, University of Central Florida, Orlando, FL 32816, United States of America
| |
Collapse
|
9
|
Xiao C, Chen CC, Maier J. Discrete modeling of ionic space charge zones in solids. Phys Chem Chem Phys 2022; 24:11945-11957. [PMID: 35522234 DOI: 10.1039/d1cp05293d] [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
The discrete model of space charge zones in solids reveals and remedies a variety of problems with the classic continuous Gouy-Chapman solution that occur for pronounced space charge potentials. Besides inherent problems of internal consistency, it is essentially the extremely steep profile close to the interface which makes this continuum approach questionable. Not only is quasi-1D discrete modeling a sensible approach for large space charge effects, it can also favorably be combined with the continuum description. A particularly useful application is the explicit implementation of crystallographic details and non-idealities close to the interface. This enables us to consider elastic, structural or saturation effects as well as permittivity variations in a simple but realistic way. We address details of the charge carrier profiles, but also overall properties such as space charge capacitance and space charge resistance. In the latter case the difference in the total charge (at identical concentration) is of importance, in the first case it is the inherent difference in the centroid of charge (at identical total charge) that is remarkable. The model is equally applicable for ionic charge carriers and small polarons.
Collapse
Affiliation(s)
- Chuanlian Xiao
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.
| | - Chia-Chin Chen
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.
| | - Joachim Maier
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.
| |
Collapse
|
10
|
Shi BX, Kapil V, Zen A, Chen J, Alavi A, Michaelides A. General embedded cluster protocol for accurate modeling of oxygen vacancies in metal-oxides. J Chem Phys 2022; 156:124704. [DOI: 10.1063/5.0087031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The O vacancy (Ov) formation energy, EOv, is an important property of a metal-oxide, governing its performance in applications such as fuel cells or heterogeneous catalysis. These defects are routinely studied with density functional theory (DFT). However, it is well-recognized that standard DFT formulations (e.g., the generalized gradient approximation) are insufficient for modeling the Ov, requiring higher levels of theory. The embedded cluster method offers a promising approach to compute EOv accurately, giving access to all electronic structure methods. Central to this approach is the construction of quantum(-mechanically treated) clusters placed within suitable embedding environments. Unfortunately, current approaches to constructing the quantum clusters either require large system sizes, preventing application of high-level methods, or require significant manual input, preventing investigations of multiple systems simultaneously. In this work, we present a systematic and general quantum cluster design protocol that can determine small converged quantum clusters for studying the Ov in metal-oxides with accurate methods, such as local coupled cluster with single, double, and perturbative triple excitations. We apply this protocol to study the Ov in the bulk and surface planes of rutile TiO2 and rock salt MgO, producing the first accurate and well-converged determinations of EOv with this method. These reference values are used to benchmark exchange–correlation functionals in DFT, and we find that all the studied functionals underestimate EOv, with the average error decreasing along the rungs of Jacob’s ladder. This protocol is automatable for high-throughput calculations and can be generalized to study other point defects or adsorbates.
Collapse
Affiliation(s)
- Benjamin X. Shi
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Venkat Kapil
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Churchill College, University of Cambridge, Storey’s Way, Cambridge CB3 0DS, United Kingdom
| | - Andrea Zen
- Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II, Monte S. Angelo, I-80126 Napoli, Italy
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ji Chen
- School of Physics, Peking University, Beijing 100871, China
| | - Ali Alavi
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Angelos Michaelides
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Thomas Young Centre and London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| |
Collapse
|
11
|
Mazheika A, Wang YG, Valero R, Viñes F, Illas F, Ghiringhelli LM, Levchenko SV, Scheffler M. Artificial-intelligence-driven discovery of catalyst genes with application to CO 2 activation on semiconductor oxides. Nat Commun 2022; 13:419. [PMID: 35058444 PMCID: PMC8776738 DOI: 10.1038/s41467-022-28042-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 01/03/2022] [Indexed: 12/31/2022] Open
Abstract
Catalytic-materials design requires predictive modeling of the interaction between catalyst and reactants. This is challenging due to the complexity and diversity of structure-property relationships across the chemical space. Here, we report a strategy for a rational design of catalytic materials using the artificial intelligence approach (AI) subgroup discovery. We identify catalyst genes (features) that correlate with mechanisms that trigger, facilitate, or hinder the activation of carbon dioxide (CO2) towards a chemical conversion. The AI model is trained on first-principles data for a broad family of oxides. We demonstrate that surfaces of experimentally identified good catalysts consistently exhibit combinations of genes resulting in a strong elongation of a C-O bond. The same combinations of genes also minimize the OCO-angle, the previously proposed indicator of activation, albeit under the constraint that the Sabatier principle is satisfied. Based on these findings, we propose a set of new promising catalyst materials for CO2 conversion.
Collapse
Affiliation(s)
- Aliaksei Mazheika
- The NOMAD Laboratory at the Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195, Berlin-Dahlem, Germany.
| | - Yang-Gang Wang
- The NOMAD Laboratory at the Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195, Berlin-Dahlem, Germany
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 518055, Shenzhen, Guangdong, China
| | - Rosendo Valero
- Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1, Barcelona, 08028, Spain
- Zhejiang Huayou Cobalt Co.,Ltd., No. 18 Wuzhen East Road, Tongxiang Economic Development Zone, 314500, Jiaxing, Zhejiang, China
| | - Francesc Viñes
- Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1, Barcelona, 08028, Spain
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1, Barcelona, 08028, Spain
| | - Luca M Ghiringhelli
- The NOMAD Laboratory at the Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195, Berlin-Dahlem, Germany
- The NOMAD Laboratory at the Humboldt University of Berlin, 12489, Berlin, Germany
| | - Sergey V Levchenko
- Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Bolshoy Boulevard 30, bld. 1, 121205, Moscow, Russia.
| | - Matthias Scheffler
- The NOMAD Laboratory at the Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195, Berlin-Dahlem, Germany
- The NOMAD Laboratory at the Humboldt University of Berlin, 12489, Berlin, Germany
| |
Collapse
|
12
|
Mitra A, Pham HQ, Pandharkar R, Hermes MR, Gagliardi L. Excited States of Crystalline Point Defects with Multireference Density Matrix Embedding Theory. J Phys Chem Lett 2021; 12:11688-11694. [PMID: 34843250 DOI: 10.1021/acs.jpclett.1c03229] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Accurate and affordable methods to characterize the electronic structure of solids are important for targeted materials design. Embedding-based methods provide an appealing balance in the trade-off between cost and accuracy─particularly when studying localized phenomena. Here, we use the density matrix embedding theory (DMET) algorithm to study the electronic excitations in solid-state defects with a restricted open-shell Hartree-Fock (ROHF) bath and multireference impurity solvers, specifically, complete active space self-consistent field (CASSCF) and n-electron valence state second-order perturbation theory (NEVPT2). We apply the method to investigate the electronic excitations in an oxygen vacancy (OV) on a MgO(100) surface and find absolute deviations within 0.05 eV between DMET using the CASSCF/NEVPT2 solver, denoted as CAS-DMET/NEVPT2-DMET, and the nonembedded CASSCF/NEVPT2 approach. Next, we establish the practicality of DMET by extending it to larger supercells for the OV defect and a neutral silicon vacancy in diamond where the use of nonembedded CASSCF/NEVPT2 is extremely expensive.
Collapse
Affiliation(s)
- Abhishek Mitra
- Department of Chemistry, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Hung Q Pham
- Department of Chemistry, University of Minnesota Twin Cities, Smith Hall, 207 Pleasant St SE, Minneapolis, Minnesota 55455-0431, United States
| | - Riddhish Pandharkar
- Department of Chemistry, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Matthew R Hermes
- Department of Chemistry, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Laura Gagliardi
- Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
- Department of Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| |
Collapse
|
13
|
Hofmann OT, Zojer E, Hörmann L, Jeindl A, Maurer RJ. First-principles calculations of hybrid inorganic-organic interfaces: from state-of-the-art to best practice. Phys Chem Chem Phys 2021; 23:8132-8180. [PMID: 33875987 PMCID: PMC8237233 DOI: 10.1039/d0cp06605b] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/05/2021] [Indexed: 12/18/2022]
Abstract
The computational characterization of inorganic-organic hybrid interfaces is arguably one of the technically most challenging applications of density functional theory. Due to the fundamentally different electronic properties of the inorganic and the organic components of a hybrid interface, the proper choice of the electronic structure method, of the algorithms to solve these methods, and of the parameters that enter these algorithms is highly non-trivial. In fact, computational choices that work well for one of the components often perform poorly for the other. As a consequence, default settings for one materials class are typically inadequate for the hybrid system, which makes calculations employing such settings inefficient and sometimes even prone to erroneous results. To address this issue, we discuss how to choose appropriate atomistic representations for the system under investigation, we highlight the role of the exchange-correlation functional and the van der Waals correction employed in the calculation and we provide tips and tricks how to efficiently converge the self-consistent field cycle and to obtain accurate geometries. We particularly focus on potentially unexpected pitfalls and the errors they incur. As a summary, we provide a list of best practice rules for interface simulations that should especially serve as a useful starting point for less experienced users and newcomers to the field.
Collapse
Affiliation(s)
- Oliver T Hofmann
- Institute of Solid State Physics, Graz University of Technology, NAWI Graz, Petersgasse 16/II, 8010 Graz, Austria.
| | - Egbert Zojer
- Institute of Solid State Physics, Graz University of Technology, NAWI Graz, Petersgasse 16/II, 8010 Graz, Austria.
| | - Lukas Hörmann
- Institute of Solid State Physics, Graz University of Technology, NAWI Graz, Petersgasse 16/II, 8010 Graz, Austria.
| | - Andreas Jeindl
- Institute of Solid State Physics, Graz University of Technology, NAWI Graz, Petersgasse 16/II, 8010 Graz, Austria.
| | - Reinhard J Maurer
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| |
Collapse
|
14
|
Chagas da Silva M, Lorke M, Aradi B, Farzalipour Tabriz M, Frauenheim T, Rubio A, Rocca D, Deák P. Self-Consistent Potential Correction for Charged Periodic Systems. PHYSICAL REVIEW LETTERS 2021; 126:076401. [PMID: 33666477 DOI: 10.1103/physrevlett.126.076401] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 11/24/2020] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
Supercell models are often used to calculate the electronic structure of local deviations from the ideal periodicity in the bulk or on the surface of a crystal or in wires. When the defect or adsorbent is charged, a jellium counter charge is applied to maintain overall neutrality, but the interaction of the artificially repeated charges has to be corrected, both in the total energy and in the one-electron eigenvalues and eigenstates. This becomes paramount in slab or wire calculations, where the jellium counter charge may induce spurious states in the vacuum. We present here a self-consistent potential correction scheme and provide successful tests of it for bulk and slab calculations.
Collapse
Affiliation(s)
- Mauricio Chagas da Silva
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, Geb. 99 ((Center for Free-Electron Laser Science - CFEL)), 22761 Hamburg, Germany
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), F-54000 Nancy, France
| | - Michael Lorke
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
| | - Bálint Aradi
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
| | - Meisam Farzalipour Tabriz
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
- Max Planck Computing and Data Facility, Gießenbachstr. 2, D-85748 Garching, Germany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
- Computational Science Research Center, No.10 East Xibeiwang Road, Beijing 100193, China and Computational Science and Applied Research Institute (CSAR), Shenzhen 518110, China
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, Geb. 99 ((Center for Free-Electron Laser Science - CFEL)), 22761 Hamburg, Germany
- Nano-Bio Spectroscopy Group, Departamento de Fisica de Materiales, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018 San Sebastián, Spain
| | - Dario Rocca
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), F-54000 Nancy, France
| | - Peter Deák
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
| |
Collapse
|
15
|
Sutton C, Levchenko SV. First-Principles Atomistic Thermodynamics and Configurational Entropy. Front Chem 2020; 8:757. [PMID: 33425844 PMCID: PMC7793851 DOI: 10.3389/fchem.2020.00757] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/21/2020] [Indexed: 11/13/2022] Open
Abstract
In most applications, functional materials operate at finite temperatures and are in contact with a reservoir of atoms or molecules (gas, liquid, or solid). In order to understand the properties of materials at realistic conditions, statistical effects associated with configurational sampling and particle exchange at finite temperatures must consequently be taken into account. In this contribution, we discuss the main concepts behind equilibrium statistical mechanics. We demonstrate how these concepts can be used to predict the behavior of materials at realistic temperatures and pressures within the framework of atomistic thermodynamics. We also introduce and discuss methods for calculating phase diagrams of bulk materials and surfaces as well as point defect concentrations. In particular, we describe approaches for calculating the configurational density of states, which requires the evaluation of the energies of a large number of configurations. The cluster expansion method is therefore also discussed as a numerically efficient approach for evaluating these energies.
Collapse
Affiliation(s)
- Christopher Sutton
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, United States
| | - Sergey V Levchenko
- Skolkovo Innovation Center, Skolkovo Institute of Science and Technology, Moscow, Russia
| |
Collapse
|
16
|
da Silva Alvim R, Ribeiro FN, Dalpian GM. Iron and oxygen vacancies at the hematite surface: pristine case and with a chlorine adatom. Phys Chem Chem Phys 2020; 22:25380-25389. [PMID: 33140776 DOI: 10.1039/d0cp03798b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Defect complexes play critical roles in the dynamics of water molecules in photoelectrochemical cell devices. For the specific case of hematite (α-Fe2O3), iron and oxygen vacancies are said to mediate the water splitting process through the localization of optically-derived charges. Using first-principles methods based on density-functional theory we show that both iron and oxygen vacancies can be observed at the surface. For an oxygen-rich environment, usually under wet conditions, the charged iron vacancies should be more frequent. As sea water would be an ideal electrolyte for this kind of device, we have also analyzed the effect of additional chlorine adsorption on this surface. While the chlorine adatom kills the charged oxygen vacancies, entering the void sites, it will not react with the iron vacancies, keeping them active during water splitting processes.
Collapse
Affiliation(s)
- Raphael da Silva Alvim
- Centro de Ciências Naturais e Humanas Universidade Federal do ABC Santo André, SP 09210-580, Brazil.
| | | | | |
Collapse
|
17
|
Taucher T, Hofmann OT, Zojer E. Final-State Simulations of Core-Level Binding Energies at Metal-Organic Hybrid Interfaces: Artifacts Caused by Spurious Collective Electrostatic Effects. ACS OMEGA 2020; 5:25868-25881. [PMID: 33073112 PMCID: PMC7557941 DOI: 10.1021/acsomega.0c03209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/14/2020] [Indexed: 05/08/2023]
Abstract
Core-level energies are frequently calculated to explain the X-ray photoelectron spectra of metal-organic hybrid interfaces. The current paper describes how such simulations can be flawed when modeling interfaces between physisorbed organic molecules and metals. The problem occurs when applying periodic boundary conditions to correctly describe extended interfaces and simultaneously considering core hole excitations in the framework of a final-state approach to account for screening effects. Since the core hole is generated in every unit cell, an artificial dipole layer is formed. In this work, we study methane on an Al(100) surface as a deliberately chosen model system for hybrid interfaces to evaluate the impact of this computational artifact. We show that changing the supercell size leads to artificial shifts in the calculated core-level energies that can be well beyond 1 eV for small cells. The same applies to atoms at comparably large distances from the substrate, encountered, for example, in extended, upright-standing adsorbate molecules. We also argue that the calculated work function change due to a core-level excitation can serve as an indication for the occurrence of such an artifact and discuss possible remedies for the problem.
Collapse
|
18
|
Kropp T, Mavrikakis M. Brønsted–Evans–Polanyi relation for CO oxidation on metal oxides following the Mars–van Krevelen mechanism. J Catal 2019. [DOI: 10.1016/j.jcat.2019.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
19
|
Misra D, Yadav SK. Prediction of Site Preference of Implanted Transition Metal Dopants in Rock-salt Oxides. Sci Rep 2019; 9:12593. [PMID: 31467380 PMCID: PMC6715737 DOI: 10.1038/s41598-019-49011-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/16/2019] [Indexed: 11/09/2022] Open
Abstract
Transition metals (TMs) implanted in oxides with rock-salt crystal structures (for example MgO and BaO) are assumed to substitute cations (Mg in case of MgO) from the lattice sites. We show that not all implanted TMs substitute cations but can be stable in interstitial sites as well. Stability of TM (Sc-Zn) dopants in various charge states in MgO and BaO has been investigated in the framework of density functional theory. We propose an effective way to calculate stability of implanted metals that let us predict site preference (interstitial or substitution) of the dopant in the host. We find that two factors govern the preference for an interstitial site: (i) relative ionic radius and (ii) relative oxygen affinity of cation and the TM dopants. If the radius of the cation is much larger than TM dopant, as in BaO, TM atoms always sit at interstitial sites. On the other hand, if the radius of the cation is comparable to that of the dopant TM, as in case of MgO, the transition of the preferred defect site, from substituting lattice Mg atom (Sc to Mn) to occupying interstitial site (Fe to Zn) is observed. This transition can be attributed to the change in the oxygen affinity of the TM atoms from Sc to Zn. Our results also explain experiments on Ni and Fe atoms implanted in MgO. TM dopants at interstitial sites could show substantially different and new properties from substitutionally doped stable compounds.
Collapse
Affiliation(s)
- Debolina Misra
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
| | - Satyesh K Yadav
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
| |
Collapse
|
20
|
Kropp T, Lu Z, Li Z, Chin YHC, Mavrikakis M. Anionic Single-Atom Catalysts for CO Oxidation: Support-Independent Activity at Low Temperatures. ACS Catal 2019. [DOI: 10.1021/acscatal.8b03298] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas Kropp
- Department of Chemical and Biological Engineering, University of Wisconsin—Madison, 1415 Engineering Drive, Madison, Wisconsin 53706-1607, United States
| | - Zhuole Lu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Zhao Li
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Ya-Huei Cathy Chin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin—Madison, 1415 Engineering Drive, Madison, Wisconsin 53706-1607, United States
| |
Collapse
|
21
|
Zhou G, Zhang Q, Zheng F, Zhang D, Liu C, Wang X, Song CL, He K, Ma XC, Gu L, Zhang P, Wang L, Xue QK. Interface enhanced superconductivity in monolayer FeSe films on MgO(001): charge transfer with atomic substitution. Sci Bull (Beijing) 2018; 63:747-752. [PMID: 36658947 DOI: 10.1016/j.scib.2018.05.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 01/21/2023]
Abstract
Interface enhanced superconductivity over 50 K has been discovered in monolayer FeSe films grown on several TiO2-terminated oxide substrates. Whether such phenomenon exists in other oxide substrates remains an extremely interesting topic. Here we report enhanced superconductivity with an onset transition temperature of 18 K in monolayer FeSe on MgO(001) substrate by transport measurement. Scanning transmission electron microscopy investigation on the interface structure indicates that FeSe films grow epitaxially on MgO(001) and that overlayer Fe atoms diffuse into the top two layers of MgO and substitute Mg atoms. Our density functional theory calculations reveal that this substitution promotes the charge transfer from the MgO substrate to the FeSe films, an essential process that also occurs in monolayer FeSe on TiO2-terminated oxides and contributes to the enhanced superconductivity therein. Our finding suggests that superconductivity enhancement in monolayer FeSe films on oxides substrates is rather general as long as charge transfer is allowed at the interface, thus pointing out an explicit direction for searching for new high temperature superconductivity by interface engineering.
Collapse
Affiliation(s)
- Guanyu Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Qinghua Zhang
- Laboratory for Advanced Materials & Electron Microscopy, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Fawei Zheng
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Ding Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Chong Liu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Xiaoxiao Wang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Can-Li Song
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Ke He
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Xu-Cun Ma
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Lin Gu
- Laboratory for Advanced Materials & Electron Microscopy, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
| | - Ping Zhang
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China.
| | - Lili Wang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
| | - Qi-Kun Xue
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
| |
Collapse
|
22
|
Brenes R, Eames C, Bulović V, Islam MS, Stranks SD. The Impact of Atmosphere on the Local Luminescence Properties of Metal Halide Perovskite Grains. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706208. [PMID: 29512205 DOI: 10.1002/adma.201706208] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/17/2017] [Indexed: 05/24/2023]
Abstract
Metal halide perovskites are exceptional candidates for inexpensive yet high-performing optoelectronic devices. Nevertheless, polycrystalline perovskite films are still limited by nonradiative losses due to charge carrier trap states that can be affected by illumination. Here, in situ microphotoluminescence measurements are used to elucidate the impact of light-soaking individual methylammonium lead iodide grains in high-quality polycrystalline films while immersing them with different atmospheric environments. It is shown that emission from each grain depends sensitively on both the environment and the nature of the specific grain, i.e., whether it shows good (bright grain) or poor (dark grain) luminescence properties. It is found that the dark grains show substantial rises in emission, while the bright grain emission is steady when illuminated in the presence of oxygen and/or water molecules. The results are explained using density functional theory calculations, which reveal strong adsorption energies of the molecules to the perovskite surfaces. It is also found that oxygen molecules bind particularly strongly to surface iodide vacancies which, in the presence of photoexcited electrons, lead to efficient passivation of the carrier trap states that arise from these vacancies. The work reveals a unique insight into the nature of nonradiative decay and the impact of atmospheric passivation on the microscale properties of perovskite films.
Collapse
Affiliation(s)
- Roberto Brenes
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | | | - Vladimir Bulović
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - M Saiful Islam
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK
| | - Samuel D Stranks
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| |
Collapse
|
23
|
Paul JT, Singh AK, Dong Z, Zhuang H, Revard BC, Rijal B, Ashton M, Linscheid A, Blonsky M, Gluhovic D, Guo J, Hennig RG. Computational methods for 2D materials: discovery, property characterization, and application design. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:473001. [PMID: 29022886 DOI: 10.1088/1361-648x/aa9305] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The discovery of two-dimensional (2D) materials comes at a time when computational methods are mature and can predict novel 2D materials, characterize their properties, and guide the design of 2D materials for applications. This article reviews the recent progress in computational approaches for 2D materials research. We discuss the computational techniques and provide an overview of the ongoing research in the field. We begin with an overview of known 2D materials, common computational methods, and available cyber infrastructures. We then move onto the discovery of novel 2D materials, discussing the stability criteria for 2D materials, computational methods for structure prediction, and interactions of monolayers with electrochemical and gaseous environments. Next, we describe the computational characterization of the 2D materials' electronic, optical, magnetic, and superconducting properties and the response of the properties under applied mechanical strain and electrical fields. From there, we move on to discuss the structure and properties of defects in 2D materials, and describe methods for 2D materials device simulations. We conclude by providing an outlook on the needs and challenges for future developments in the field of computational research for 2D materials.
Collapse
Affiliation(s)
- J T Paul
- Department of Materials Science and Engineering, University of Florida, Gainesville, Fl 32611, United States of America
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Perdew JP, Yang W, Burke K, Yang Z, Gross EKU, Scheffler M, Scuseria GE, Henderson TM, Zhang IY, Ruzsinszky A, Peng H, Sun J, Trushin E, Görling A. Understanding band gaps of solids in generalized Kohn-Sham theory. Proc Natl Acad Sci U S A 2017; 114:2801-2806. [PMID: 28265085 PMCID: PMC5358356 DOI: 10.1073/pnas.1621352114] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The fundamental energy gap of a periodic solid distinguishes insulators from metals and characterizes low-energy single-electron excitations. However, the gap in the band structure of the exact multiplicative Kohn-Sham (KS) potential substantially underestimates the fundamental gap, a major limitation of KS density-functional theory. Here, we give a simple proof of a theorem: In generalized KS theory (GKS), the band gap of an extended system equals the fundamental gap for the approximate functional if the GKS potential operator is continuous and the density change is delocalized when an electron or hole is added. Our theorem explains how GKS band gaps from metageneralized gradient approximations (meta-GGAs) and hybrid functionals can be more realistic than those from GGAs or even from the exact KS potential. The theorem also follows from earlier work. The band edges in the GKS one-electron spectrum are also related to measurable energies. A linear chain of hydrogen molecules, solid aluminum arsenide, and solid argon provide numerical illustrations.
Collapse
Affiliation(s)
- John P Perdew
- Department of Physics, Temple University, Philadelphia, PA 19122;
- Department of Chemistry, Temple University, Philadelphia, PA 19122
| | - Weitao Yang
- Department of Chemistry, Duke University, Durham, NC 27708
| | - Kieron Burke
- Department of Chemistry, University of California, Irvine, CA 92697
- Department of Physics, University of California, Irvine, CA 92697
| | - Zenghui Yang
- Department of Physics, Temple University, Philadelphia, PA 19122
| | | | - Matthias Scheffler
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106
- Materials Department, University of California, Santa Barbara, CA 93106
| | - Gustavo E Scuseria
- Department of Chemistry, Rice University, Houston, TX 77005
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
| | - Thomas M Henderson
- Department of Chemistry, Rice University, Houston, TX 77005
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
| | - Igor Ying Zhang
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | | | - Haowei Peng
- Department of Physics, Temple University, Philadelphia, PA 19122
| | - Jianwei Sun
- Department of Physics, The University of Texas at El Paso, El Paso, TX 79968
| | - Egor Trushin
- Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Andreas Görling
- Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| |
Collapse
|
25
|
Global and local aspects of the surface potential landscape for energy level alignment at organic-ZnO interfaces. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2016.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
26
|
Hemmingson SL, Campbell CT. Trends in Adhesion Energies of Metal Nanoparticles on Oxide Surfaces: Understanding Support Effects in Catalysis and Nanotechnology. ACS NANO 2017; 11:1196-1203. [PMID: 28045491 DOI: 10.1021/acsnano.6b07502] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nanoparticles on surfaces are ubiquitous in nanotechnologies, especially in catalysis, where metal nanoparticles anchored to oxide supports are widely used to produce and use fuels and chemicals, and in pollution abatement. We show that for hemispherical metal particles of the same diameter, D, the chemical potentials of the metal atoms in the particles (μM) differ between two supports by approximately -2(Eadh,A - Eadh,B)Vm/D, where Ead,i is the adhesion energy between the metal and support i, and Vm is the molar volume of the bulk metal. This is consistent with calorimetric measurements of metal vapor adsorption energies onto clean oxide surfaces where the metal grows as 3D particles, which proved that μM increases with decreasing particle size below 6 nm and, for a given size, decreases with Eadh. Since catalytic activity and sintering rates correlate with metal chemical potential, it is thus crucial to understand what properties of catalyst materials control metal/oxide adhesion energies. Trends in how Eadh varies with the metal and the support oxide are presented. For a given oxide, Eadh increases linearly from metal to metal with increasing heat of formation of the most stable oxide of the metal (per mole metal), or metal oxophilicity, suggesting that metal-oxygen bonds dominate interfacial bonding. For the two different stoichiometric oxide surfaces that have been studied on multiple metals (MgO(100) and CeO2(111), the slopes of these lines are the same, but their offset is large (∼2 J/m2). Adhesion energies increase as MgO(100) ≈ TiO2(110) < α-Al2O3(0001) < CeO2(111) ≈ Fe3O4(111).
Collapse
Affiliation(s)
- Stephanie L Hemmingson
- Department of Chemistry University of Washington Seattle, Washington 98195-1700, United States
| | - Charles T Campbell
- Department of Chemistry University of Washington Seattle, Washington 98195-1700, United States
| |
Collapse
|
27
|
Kubas A, Berger D, Oberhofer H, Maganas D, Reuter K, Neese F. Surface Adsorption Energetics Studied with "Gold Standard" Wave-Function-Based Ab Initio Methods: Small-Molecule Binding to TiO 2(110). J Phys Chem Lett 2016; 7:4207-4212. [PMID: 27690453 DOI: 10.1021/acs.jpclett.6b01845] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Coupled-cluster theory with single, double, and perturbative triple excitations (CCSD(T)) is widely considered to be the "gold standard" of ab initio quantum chemistry. Using the domain-based pair natural orbital local correlation concept (DLPNO-CCSD(T)), these calculations can be performed on systems with hundreds of atoms at an accuracy of ∼99.9% of the canonical CCSD(T) method. This allows for ab initio calculations providing reference adsorption energetics at solid surfaces with an accuracy approaching 1 kcal/mol. This is an invaluable asset, not least for the assessment of density functional theory (DFT) as the prevalent approach for large-scale production calculations in energy or catalysis applications. Here we use DLPNO-CCSD(T) with embedded cluster models to compute entire adsorbate potential energy surfaces for the binding of a set of prototypical closed-shell molecules (H2O, NH3, CH4, CH3OH, CO2) to the rutile TiO2(110) surface. The DLPNO-CCSD(T) calculations show excellent agreement with available experimental data, even for the "infamous" challenge of correctly predicting the CO2 adsorption geometry. The numerical efficiency of the approach is within 1 order of magnitude of hybrid-level DFT calculations, hence blurring the borders between reference and production technique.
Collapse
Affiliation(s)
- Adam Kubas
- Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Daniel Berger
- Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München , Lichtenbergstr. 4, 85747 Garching, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München , Lichtenbergstr. 4, 85747 Garching, Germany
| | - Dimitrios Maganas
- Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Karsten Reuter
- Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München , Lichtenbergstr. 4, 85747 Garching, Germany
| | - Frank Neese
- Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| |
Collapse
|
28
|
Ren XY, Kim HJ, Niu CY, Jia Y, Cho JH. Origin of Symmetric Dimer Images of Si(001) Observed by Low-Temperature Scanning Tunneling Microscopy. Sci Rep 2016; 6:27868. [PMID: 27292000 PMCID: PMC4904415 DOI: 10.1038/srep27868] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/26/2016] [Indexed: 11/09/2022] Open
Abstract
It has been a long-standing puzzle why buckled dimers of the Si(001) surface appeared symmetric below ~20 K in scanning tunneling microscopy (STM) experiments. Although such symmetric dimer images were concluded to be due to an artifact induced by STM measurements, its underlying mechanism is still veiled. Here, we demonstrate, based on a first-principles density-functional theory calculation, that the symmetric dimer images are originated from the flip-flop motion of buckled dimers, driven by quantum tunneling (QT). It is revealed that at low temperature the tunneling-induced surface charging with holes reduces the energy barrier for the flipping of buckled dimers, thereby giving rise to a sizable QT-driven frequency of the flip-flop motion. However, such a QT phenomenon becomes marginal in the tunneling-induced surface charging with electrons. Our findings provide an explanation for low-temperature STM data that exhibits apparent symmetric (buckled) dimer structure in the filled-state (empty-state) images.
Collapse
Affiliation(s)
- Xiao-Yan Ren
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Korea.,School of Mechanical and Electrical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, China
| | - Hyun-Jung Kim
- Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Korea.,Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722, Korea
| | - Chun-Yao Niu
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Center for Advanced Analysis and Computational Science, Zhengzhou University, Zhengzhou 45001, China
| | - Yu Jia
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Center for Advanced Analysis and Computational Science, Zhengzhou University, Zhengzhou 45001, China
| | - Jun-Hyung Cho
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Korea.,International Center for Quantum Design of Functional Materials (ICQD), HFNL, University of Science and Technology of China, Hefei, Anhui 230026, China
| |
Collapse
|
29
|
Logsdail AJ, Downing CA, Keal TW, Sherwood P, Sokol AA, Catlow CRA. Modelling the chemistry of Mn-doped MgO for bulk and (100) surfaces. Phys Chem Chem Phys 2016; 18:28648-28660. [DOI: 10.1039/c6cp04622c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have investigated the energetic properties of Mn-doped MgO bulk and (100) surfaces using a QM/MM embedding computational method, calculating the formation energy for doped systems, as well as for surface defects, and the subsequent effect on chemical reactivity.
Collapse
Affiliation(s)
- Andrew J. Logsdail
- Kathleen Lonsdale Materials Chemistry
- Department of Chemistry
- University College London
- London
- UK
| | - Christopher A. Downing
- Kathleen Lonsdale Materials Chemistry
- Department of Chemistry
- University College London
- London
- UK
| | - Thomas W. Keal
- Scientific Computing Department
- STFC Daresbury Laboratory
- Warrington
- UK
| | - Paul Sherwood
- Scientific Computing Department
- STFC Daresbury Laboratory
- Warrington
- UK
| | - Alexey A. Sokol
- Kathleen Lonsdale Materials Chemistry
- Department of Chemistry
- University College London
- London
- UK
| | - C. Richard A. Catlow
- Kathleen Lonsdale Materials Chemistry
- Department of Chemistry
- University College London
- London
- UK
| |
Collapse
|
30
|
Schwach P, Frandsen W, Willinger MG, Schlögl R, Trunschke A. Structure sensitivity of the oxidative activation of methane over MgO model catalysts: I. Kinetic study. J Catal 2015. [DOI: 10.1016/j.jcat.2015.05.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
31
|
|
32
|
|
33
|
Schuler T, Barouh C, Nastar M, Fu CC. Equilibrium Vacancy Concentration Driven by Undetectable Impurities. PHYSICAL REVIEW LETTERS 2015; 115:015501. [PMID: 26182104 DOI: 10.1103/physrevlett.115.015501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Indexed: 06/04/2023]
Abstract
By means of ab initio calculations combined to statistical mechanics, we provide new evidence that an experimentally undetectable tiny amount of impurities can be responsible for drastic changes in vacancy concentrations ([V]), inducing large deviations from an Arrhenius law even at low temperature. It is the case of O and N in α-Fe. The present finding is fully compatible with existing experiments, and changes the previous common vision that C has the dominant effect. This study provides a route for bridging the longstanding theoretical-experimental gap on the prediction of [V] in metals.
Collapse
Affiliation(s)
- Thomas Schuler
- CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette, France
| | - Caroline Barouh
- CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette, France
| | - Maylise Nastar
- CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette, France
| | - Chu-Chun Fu
- CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette, France
| |
Collapse
|
34
|
Wang D, Han D, Li XB, Xie SY, Chen NK, Tian WQ, West D, Sun HB, Zhang SB. Determination of formation and ionization energies of charged defects in two-dimensional materials. PHYSICAL REVIEW LETTERS 2015; 114:196801. [PMID: 26024189 DOI: 10.1103/physrevlett.114.196801] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Indexed: 06/04/2023]
Abstract
We present a simple and efficient approach to evaluate the formation energy and, in particular, the ionization energy (IE) of charged defects in two-dimensional (2D) systems using the supercell approximation. So far, first-principles results for such systems can scatter widely due to the divergence of the Coulomb energy with vacuum dimension, denoted here as L_{z}. Numerous attempts have been made in the past to fix the problem under various approximations. Here, we show that the problem can be resolved without any such assumption, and a converged IE can be obtained by an extrapolation of the asymptotic IE expression at large L_{z} (with a fixed lateral area S) back to the value at L_{z}=0. Application to defects in monolayer boron nitride reveal that defects in 2D systems can be unexpectedly deep, much deeper than the bulk.
Collapse
Affiliation(s)
- Dan Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Dong Han
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Xian-Bin Li
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Sheng-Yi Xie
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Nian-Ke Chen
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Wei Quan Tian
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- Institute of Theoretical Chemistry, Jilin University, Changchun 130012, China
| | - Damien West
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Hong-Bo Sun
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - S B Zhang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| |
Collapse
|
35
|
|
36
|
Abstract
A heterogeneous catalyst is a functional material that continually creates active sites with its reactants under reaction conditions. These sites change the rates of chemical reactions of the reactants localized on them without changing the thermodynamic equilibrium between the materials.
Collapse
Affiliation(s)
- Robert Schlögl
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany) http://www.fhi-berlin.mpg.de http://www.cec.mpg.de; Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim a.d. Ruhr (Germany).
| |
Collapse
|
37
|
Li YF, Aschauer U, Chen J, Selloni A. Adsorption and reactions of O2 on anatase TiO2. Acc Chem Res 2014; 47:3361-8. [PMID: 24742024 DOI: 10.1021/ar400312t] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CONSPECTUS: The interaction of molecular oxygen with titanium dioxide (TiO2) surfaces plays a key role in many technologically important processes such as catalytic oxidation reactions, chemical sensing, and photocatalysis. While O2 interacts weakly with fully oxidized TiO2, excess electrons are often present in TiO2 samples. These excess electrons originate from intrinsic reducing defects (oxygen vacancies and titanium interstitials), doping, or photoexcitation and form polaronic Ti(3+) states in the band gap near the bottom of the conduction band. Oxygen adsorption involves the transfer of one or more of these excess electrons to an O2 molecule at the TiO2 surface. This results in an adsorbed superoxo (O2(-)) or peroxo (O2(2-)) species or in molecular dissociation and formation of two oxygen adatoms (2 × O(2-)). Oxygen adsorption is also the first step toward oxygen incorporation, a fundamental reaction that strongly affects the chemical properties and charge-carrier densities; for instance, it can transform the material from an n-type semiconductor to a poor electronic conductor. In this Account, we present an overview of recent theoretical work on O2 adsorption and reactions on the reduced anatase (101) surface. Anatase is the TiO2 polymorph that is generally considered most active in photocatalysis. Experiments on anatase powders have shown that the properties of photoexcited electrons are similar to those of excess electrons from reducing defects, and therefore, oxygen on reduced anatase is also a model system for studying the role of O2 in photocatalysis. Experimentally, the characteristic Ti(3+) defect states disappear after adsorption of molecular oxygen, which indicates that the excess electrons are indeed trapped by O2. Moreover, superoxide surface species associated with two different cation surface sites, possibly a regular cation site and a cation close to an anion vacancy, were identified by electron paramagnetic resonance spectroscopy. On the theoretical side, however, density functional theory studies have consistently found that it is energetically more favorable for O2 to adsorb in the peroxo form rather than the superoxo form. As a result, obtaining a detailed understanding of the nature of the observed superoxide species has proven difficult for many years. On reduced anatase (101), both oxygen vacancies and Ti interstitials have been shown to reside exclusively in the susbsurface. We discuss how reaction of O2 with a subsurface O vacancy heals the vacancy while leading to the formation of a surface bridging dimer defect. Similarly, the interaction of O2 with a Ti interstitial causes migration of this defect to the surface and the formation of a surface TiO2 cluster. Finally, we analyze the peroxo and superoxo states of the adsorbed molecule. On the basis of periodic hybrid functional calculations of interfacial electron transfer between reduced anatase and O2, we show that the peroxide form, while energetically more stable, is kinetically less favorable than the superoxide form. The existence of a kinetic barrier between the superoxo and peroxo states is essential for explaining a variety of experimental observations.
Collapse
Affiliation(s)
- Ye-Fei Li
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | | | - Jia Chen
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Annabella Selloni
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
38
|
Termination chemistry-driven dislocation structure at SrTiO3/MgO heterointerfaces. Nat Commun 2014; 5:5043. [DOI: 10.1038/ncomms6043] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/21/2014] [Indexed: 11/08/2022] Open
|
39
|
Winget P, Schirra LK, Cornil D, Li H, Coropceanu V, Ndione PF, Sigdel AK, Ginley DS, Berry JJ, Shim J, Kim H, Kippelen B, Brédas JL, Monti OLA. Defect-driven interfacial electronic structures at an organic/metal-oxide semiconductor heterojunction. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:4711-4716. [PMID: 24830796 DOI: 10.1002/adma.201305351] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 04/19/2014] [Indexed: 06/03/2023]
Abstract
The electronic structure of the hybrid interface between ZnO and the prototypical organic semiconductor PTCDI is investigated via a combination of ultraviolet and X-ray photoelectron spectroscopy (UPS/XPS) and density functional theory (DFT) calculations. The interfacial electronic interactions lead to a large interface dipole due to substantial charge transfer from ZnO to 3,4,9,10-perylenetetracarboxylicdiimide (PTCDI), which can be properly described only when accounting for surface defects that confer ZnO its n-type properties.
Collapse
Affiliation(s)
- Paul Winget
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Cheng TL, Wen YH. Toward a Quantitative Understanding of the Electric Field in Thermal Metal Oxidation and a Self-Consistent Wagner Theory. J Phys Chem Lett 2014; 5:2289-2294. [PMID: 26279548 DOI: 10.1021/jz5008627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The electric field in the growing oxide film is important to the kinetics and mechanism of metal oxidation. However, understanding of the essential characteristics of the electric field during oxidation remains insufficient. A special-case analytical model is presented that provides a unified understanding for the electric field from the viewpoints of kinetics and thermodynamics. More general cases are studied by computer simulations that show similar characteristics in the electric field. In particular, simulations indicate that in many situations, the electrostatic potential drop across the bulk oxide is limited to ∼kBT/e, which means that the total electrostatic potential drop across the oxide film, if on the order of 1 V by rough estimation, should have contributions mostly from the electrified interfaces. Finally, regarding the Gibbs-Duhem relation, the commonly used isobaric assumption for the diffusing species is refuted. The results contained herein also provide a self-consistent understanding of Wagner's oxidation theory.
Collapse
Affiliation(s)
- Tian-Le Cheng
- National Energy Technology Laboratory, 1450 Queen Avenue Southwest, Albany, Oregon 97321, United States
| | - You-Hai Wen
- National Energy Technology Laboratory, 1450 Queen Avenue Southwest, Albany, Oregon 97321, United States
| |
Collapse
|
41
|
McKenna KP. Electronic and chemical properties of a surface-terminated screw dislocation in MgO. J Am Chem Soc 2013; 135:18859-65. [PMID: 24279391 PMCID: PMC3892727 DOI: 10.1021/ja408342z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Dislocations represent an important and ubiquitous class of topological defect found at the surfaces of metal oxide materials. They are thought to influence processes as diverse as crystal growth, corrosion, charge trapping, luminescence, molecular adsorption, and catalytic activity; however, their electronic and chemical properties remain poorly understood. Here, through a detailed first-principles investigation into the properties of a surface-terminated screw dislocation in MgO we provide atomistic insight into these issues. We show that surface dislocations can exhibit intriguing electron trapping properties which are important for understanding the chemical and electronic characteristics of oxide surfaces. The results presented in this article taken together with recent experimental reports show that surface dislocations can be equally as important as more commonly considered surface defects, such as steps, kinks, and vacancies, but are now just beginning to be understood.
Collapse
Affiliation(s)
- Keith P McKenna
- Department of Physics, University of York , Heslington, York YO10 5DD, United Kingdom
| |
Collapse
|
42
|
Xu Y, Hofmann OT, Schlesinger R, Winkler S, Frisch J, Niederhausen J, Vollmer A, Blumstengel S, Henneberger F, Koch N, Rinke P, Scheffler M. Space-charge transfer in hybrid inorganic-organic systems. PHYSICAL REVIEW LETTERS 2013; 111:226802. [PMID: 24329464 DOI: 10.1103/physrevlett.111.226802] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Indexed: 05/24/2023]
Abstract
We discuss density functional theory calculations of hybrid inorganic-organic systems that explicitly include the global effects of doping (i.e., position of the Fermi level) and the formation of a space-charge layer. For the example of tetrafluoro-tetracyanoquinodimethane on the ZnO(0001[over ¯]) surface we show that the adsorption energy and electron transfer depend strongly on the ZnO doping. The associated work function changes are large, for which the formation of space-charge layers is the main driving force. The prominent doping effects are expected to be quite general for charge-transfer interfaces in hybrid inorganic-organic systems and important for device design.
Collapse
Affiliation(s)
- Yong Xu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
| | - Oliver T Hofmann
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
| | | | - Stefanie Winkler
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH-BESSY II, 12489 Berlin, Germany
| | - Johannes Frisch
- Humboldt-Universität zu Berlin, Institut für Physik, 12489 Berlin, Germany
| | - Jens Niederhausen
- Humboldt-Universität zu Berlin, Institut für Physik, 12489 Berlin, Germany
| | - Antje Vollmer
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH-BESSY II, 12489 Berlin, Germany
| | - Sylke Blumstengel
- Humboldt-Universität zu Berlin, Institut für Physik, 12489 Berlin, Germany
| | - Fritz Henneberger
- Humboldt-Universität zu Berlin, Institut für Physik, 12489 Berlin, Germany
| | - Norbert Koch
- Humboldt-Universität zu Berlin, Institut für Physik, 12489 Berlin, Germany and Helmholtz-Zentrum Berlin für Materialien und Energie GmbH-BESSY II, 12489 Berlin, Germany
| | - Patrick Rinke
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
| | | |
Collapse
|
43
|
Hofmann OT, Deinert JC, Xu Y, Rinke P, Stähler J, Wolf M, Scheffler M. Large work function reduction by adsorption of a molecule with a negative electron affinity: Pyridine on ZnO(101¯0). J Chem Phys 2013; 139:174701. [DOI: 10.1063/1.4827017] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
44
|
Bhattacharya S, Levchenko SV, Ghiringhelli LM, Scheffler M. Stability and metastability of clusters in a reactive atmosphere: theoretical evidence for unexpected stoichiometries of MgMOx. PHYSICAL REVIEW LETTERS 2013; 111:135501. [PMID: 24116790 DOI: 10.1103/physrevlett.111.135501] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Indexed: 06/02/2023]
Abstract
By applying a genetic algorithm and ab initio atomistic thermodynamics, we identify the stable and metastable compositions and structures of MgMOx clusters at realistic temperatures and oxygen pressures. We find that small clusters (M≲5) are in thermodynamic equilibrium when x>M. The nonstoichiometric clusters exhibit peculiar magnetic behavior, suggesting the possibility of tuning magnetic properties by changing environmental pressure and temperature conditions. Furthermore, we show that density-functional theory with a hybrid exchange-correlation functional is needed for predicting accurate phase diagrams of metal-oxide clusters. Neither a (sophisticated) force field nor density-functional theory with (semi)local exchange-correlation functionals is sufficient for even a qualitative prediction.
Collapse
Affiliation(s)
- Saswata Bhattacharya
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | | | | | | |
Collapse
|