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Alotaibi M. Investigating the Electronic Properties and Stability of Rh 3 Clusters on Rutile TiO 2 for Potential Photocatalytic Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1051. [PMID: 38921927 PMCID: PMC11206997 DOI: 10.3390/nano14121051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/27/2024]
Abstract
Addressing the pressing needs for alternatives to fossil fuel-based energy sources, this research explores the intricate interplay between Rhodium (Rh3) clusters and titanium dioxide (TiO2) to improve photocatalytic water splitting for the generation of eco-friendly hydrogen. This research applies the density functional theory (DFT) coupled with the Hartree-Fock theory to meticulously examine the structural and electronic structures of Rh3 clusters on TiO2 (110) interfaces. Considering the photocatalytic capabilities of TiO2 and its inherent limitations in harnessing visible light, the potential for metals such as Rh3 clusters to act as co-catalysts is assessed. The results show that triangular Rh3 clusters demonstrate remarkable stability and efficacy in charge transfer when integrated into rutile TiO2 (110), undergoing oxidation in optimal adsorption conditions and altering the electronic structures of TiO2. The subsequent analysis of TiO2 surfaces exhibiting defects indicates that Rh3 clusters elevate the energy necessary for the formation of an oxygen vacancy, thereby enhancing the stability of the metal oxide. Additionally, the combination of Rh3-cluster adsorption and oxygen-vacancy formation generates polaronic and localized states, crucial for enhancing the photocatalytic activity of metal oxide in the visible light range. Through the DFT analysis, this study elucidates the importance of Rh3 clusters as co-catalysts in TiO2-based photocatalytic frameworks, paving the way for empirical testing and the fabrication of effective photocatalysts for hydrogen production. The elucidated impact on oxygen vacancy formation and electronic structures highlights the complex interplay between Rh3 clusters and TiO2 surfaces, providing insightful guidance for subsequent studies aimed at achieving clean and sustainable energy solutions.
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Affiliation(s)
- Moteb Alotaibi
- Department of Physics, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
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2
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Alotaibi M. Geometrical Stabilities and Electronic Structures of Ru 3 Clusters on Rutile TiO 2 for Green Hydrogen Production. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:396. [PMID: 38470727 PMCID: PMC10934880 DOI: 10.3390/nano14050396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/16/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024]
Abstract
In response to the vital requirement for renewable energy alternatives, this research delves into the complex interactions between ruthenium (Ru3) clusters and rutile titanium dioxide (TiO2) (110) interfaces, with the aim of enhancing photocatalytic water splitting processes to produce environmentally friendly hydrogen. As the world shifts away from traditional fossil fuels, this study utilizes the density functional theory (DFT) and the HSE06 hybrid functional to thoroughly assess the geometric and electronic properties of Ru3 clusters on rutile TiO2 (110) surfaces. Given TiO2's renown role as a photocatalyst and its limitations in visible light absorption, this research investigates the potential of metals like Ru to serve as additional catalysts. The results indicate that the triangular Ru3 cluster exhibits exceptional stability and charge transfer effectiveness when loaded on rutile TiO2 (110). Under ideal adsorption scenarios, the cluster undergoes oxidation, leading to subsequent changes in the electronic configuration of TiO2. Further exploration into TiO2 surfaces with defects shows that Ru3 clusters influence the creation of oxygen vacancies, resulting in a greater stabilization of TiO2 and an increase in the energy required for creating oxygen vacancies. Moreover, the attachment of the Ru3 cluster and the creation of oxygen vacancies lead to the emergence of polaronic and hybrid states centered on specific titanium atoms. These states are vital for enhancing the photocatalytic performance of the material within the visible light spectrum. This DFT study provides essential insights into the role of Ru3 clusters as potential supplementary catalysts in TiO2-based photocatalytic systems, setting the stage for practical experiments and the development of highly efficient photocatalysts for sustainable hydrogen generation. The observed effects on electronic structures and oxygen vacancy generation underscore the intricate relationship between Ru3 clusters and TiO2 interfaces, offering a valuable direction for future research in the pursuit of clean and sustainable energy solutions.
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Affiliation(s)
- Moteb Alotaibi
- Department of Physics, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
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3
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Alotaibi M. Geometrical Stabilities and Electronic Structures of Rh 5 Nanoclusters on Rutile TiO 2 (110) for Green Hydrogen Production. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:191. [PMID: 38251155 PMCID: PMC10819950 DOI: 10.3390/nano14020191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
Addressing the urgent need for sustainable energy sources, this study investigates the intricate relationship between rhodium (Rh5) nanoclusters and TiO2 rutile (110) surfaces, aiming to advance photocatalytic water splitting for green hydrogen production. Motivated by the imperative to transition from conventional fossil fuels, this study employs density functional theory (DFT) with DFT-D3 and HSE06 hybrid functionals to analyse the geometrical stabilities and electronic structures of Rh5 nanoclusters on TiO2 rutile (110). TiO2, a prominent photocatalyst, faces challenges such as limited visible light absorption, leading researchers to explore noble metals like Rh as cocatalysts. Our results show that bipyramidal Rh5 nanoclusters exhibit enhanced stability and charge transfer when adsorbed on TiO2 rutile (110) compared to trapezoidal configurations. The most stable adsorption induces the oxidation of the nanocluster, altering the electronic structure of TiO2. Extending the analysis to defective TiO2 surfaces, this study explores the impact of Rh5 nanoclusters on oxygen vacancy formation, revealing the stabilisation of TiO2 and increased oxygen vacancy formation energy. This theoretical exploration contributes insights into the potential of Rh5 nanoclusters as efficient cocatalysts for TiO2-based photocatalytic systems, laying the foundation for experimental validations and the rational design of highly efficient photocatalysts for sustainable hydrogen production. The observed effects on electronic structures and oxygen vacancy formation emphasize the complex interactions between Rh5 nanoclusters and the TiO2 surface, guiding future research in the quest for clean energy alternatives.
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Affiliation(s)
- Moteb Alotaibi
- Department of Physics, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
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4
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Wu Z, Yin WJ, Wen B, Ma D, Liu LM. Oxygen Vacancy Diffusion in Rutile TiO 2: Insight from Deep Neural Network Potential Simulations. J Phys Chem Lett 2023; 14:2208-2214. [PMID: 36812488 DOI: 10.1021/acs.jpclett.2c03827] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Defects play a crucial role in the surface reactivity and electronic engineering of titanium dioxide (TiO2). In this work, we have used an active learning method to train deep neural network potentials from the ab initio data of a defective TiO2 surface. Validations show a good consistency between the deep potentials (DPs) and density functional theory (DFT) results. Therefore, the DPs were further applied on the extended surface and executed for nanoseconds. The results show that the oxygen vacancy at various sites are very stable under 330 K. However, some unstable defect sites will convert to the most favorable ones after tens or hundreds of picoseconds, while the temperature was elevated to 500 K. The DP predicated barriers of oxygen vacancy diffusion were similar to those of DFT. These results show that machine-learning trained DPs could accelerate the molecular dynamics with a DFT-level accuracy and promote people's understanding of the microscopic mechanism of fundamental reactions.
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Affiliation(s)
- Zhihong Wu
- Key Laboratory for Special Functional Materials of Ministry of Education, School of Materials Science and Engineering, Henan University, Kaifeng 475004, China
| | - Wen-Jin Yin
- School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Bo Wen
- School of Physics and Electronics, Henan University, Kaifeng 475004, China
| | - Dongwei Ma
- Key Laboratory for Special Functional Materials of Ministry of Education, School of Materials Science and Engineering, Henan University, Kaifeng 475004, China
| | - Li-Min Liu
- School of Physics, Beihang University, Beijing 100083, China
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5
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ATR-FTIR in Kretschmann configuration integrated with electrochemical cell as in situ interfacial sensitive tool to study corrosion inhibitors for magnesium substrates. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.136166] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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6
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Tang M, Zhang Z, Ge Q. A DFT-based study of surface chemistries of rutile TiO2 and SnO2(110) toward formaldehyde and formic acid. Catal Today 2016. [DOI: 10.1016/j.cattod.2016.01.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Zhang W, Liu L, Wan L, Liu L, Cao L, Xu F, Zhao J, Wu Z. Electronic structures of bare and terephthalic acid adsorbed TiO2(110)-(1 × 2) reconstructed surfaces: origin and reactivity of the band gap states. Phys Chem Chem Phys 2015; 17:20144-53. [DOI: 10.1039/c5cp01298h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Ti2O3-row contributed band gap states are sensitive to TPA adsorption, resulting in the redistribution of Ti 3d states at the interface.
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Affiliation(s)
- Wenhua Zhang
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- People's Republic of China
| | - Liming Liu
- Department of Physics and Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| | - Li Wan
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- People's Republic of China
| | - Lingyun Liu
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- People's Republic of China
| | - Liang Cao
- High Magnetic Field Laboratory
- Chinese Academy of Sciences
- Hefei 230031
- P. R. China
| | - Faqiang Xu
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- People's Republic of China
| | - Jin Zhao
- Department of Physics and Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
- Synergetic Innovation Center of Quantum Information & Quantum Physics
| | - Ziyu Wu
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- People's Republic of China
- Beijing Synchrotron Radiation Laboratory
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8
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De Angelis F, Di Valentin C, Fantacci S, Vittadini A, Selloni A. Theoretical Studies on Anatase and Less Common TiO2 Phases: Bulk, Surfaces, and Nanomaterials. Chem Rev 2014; 114:9708-53. [DOI: 10.1021/cr500055q] [Citation(s) in RCA: 321] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Filippo De Angelis
- Computational
Laboratory for Hybrid Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Cristiana Di Valentin
- Dipartimento
di Scienza dei Materiali, Università di Milano-Bicocca, I-20125 Milano, Italy
| | - Simona Fantacci
- Computational
Laboratory for Hybrid Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Andrea Vittadini
- Istituto
CNR per l’Energetica e le Interfasi (IENI), c/o Dipartimento
di Scienze Chimiche, Universita’ di Padova, I-35131 Padova, Italy
| | - Annabella Selloni
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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9
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Chang TY, Tanaka Y, Ishikawa R, Toyoura K, Matsunaga K, Ikuhara Y, Shibata N. Direct imaging of Pt single atoms adsorbed on TiO2 (110) surfaces. NANO LETTERS 2014; 14:134-8. [PMID: 24351061 DOI: 10.1021/nl403520c] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Noble metal nanoparticles (e.g., gold and platinum) supported on TiO2 surfaces are utilized in many technological applications such as heterogeneous catalysts. To fully understand their enhanced catalytic activity, it is essential to unravel the interfacial interaction between the metal atoms and TiO2 surfaces at the level of atomic dimensions. However, it has been extremely difficult to directly characterize the atomic-scale structures that result when individual metal atoms are adsorbed on the TiO2 surfaces. Here, we show direct atomic-resolution images of individual Pt atoms adsorbed on TiO2 (110) surfaces using aberration-corrected scanning transmission electron microscopy. Subangstrom spatial resolution enables us to identify five different Pt atom adsorption sites on the TiO2 (110) surface. Combining this with systematic density functional theory calculations reveals that the most favorable Pt adsorption sites are on vacancy sites of basal oxygen atoms that are located in subsurface positions relative to the top surface bridging oxygen atoms.
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Affiliation(s)
- Teng-Yuan Chang
- Institute of Engineering Innovation, School of Engineering, the University of Tokyo , Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-8656, Japan
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10
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Shi H, Liu YC, Miao M, Wu T, Wang Q. Adsorption and dissociation of methanol on defective rutile TiO2 (110) surface with bridging oxygen-vacancy pairs. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.08.080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Plata JJ, Collico V, Márquez AM, Sanz JF. Analysis of the origin of lateral interactions in the adsorption of small organic molecules on oxide surfaces. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1311-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Mellan TA, Grau-Crespo R. Density functional theory study of rutile VO2 surfaces. J Chem Phys 2012; 137:154706. [DOI: 10.1063/1.4758319] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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He T, Li JL, Yang GW. Physical origin of general oscillation of structure, surface energy, and electronic property in rutile TiO2 nanoslab. ACS APPLIED MATERIALS & INTERFACES 2012; 4:2192-2198. [PMID: 22468756 DOI: 10.1021/am300193d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Titanium oxide (TiO(2)) nanostructures have been attracting consistent focus in the past few years because of their enhanced power in solar-energy conversion. Surface and interface play a crucial role in the determination of thermodynamic stability and electronic structure of TiO(2) nanostructures. The rutile (110) nanoslab (NS) has been used as a common subject to investigate the surface relaxation, defect characters, molecule adsorption, and chemically dynamic reaction of TiO(2) nanostructures. Up to date, a long-time standing issue in TiO(2) NS, i.e., the general oscillation of structure, surface energy and electronic property with changing of NS thickness, has not been clear. We have presented a comprehensive investigation on the relationship between surface and oscillation behavior in the TiO(2) (110) NS by the first-principles calculations accompanied with the wave function analysis. We clearly, for the first time, pointed out that the dipoles and surface states bonding induced by the surface-surface interactions are the physical origin of general oscillations in the TiO(2) (110) NS. Our findings not only have a new insight into the basic interactions between surfaces in TiO(2) nanostructures, but also provide useful information for tuning the photocatalytic and photovoltaic properties by surface design.
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Affiliation(s)
- T He
- State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, Guangdong, P R China
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14
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The Role of Surface and Subsurface Point Defects for Chemical Model Studies on TiO
2
: A First‐Principles Theoretical Study of Formaldehyde Bonding on Rutile TiO
2
(110). Chemistry 2011; 17:4496-506. [DOI: 10.1002/chem.201002588] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Indexed: 11/07/2022]
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15
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16
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Ortega Y, Hernández NC, Menéndez-Proupin E, Graciani J, Sanz JF. Nitrogen/gold codoping of the TiO2(101) anatase surface. A theoretical study based on DFT calculations. Phys Chem Chem Phys 2011; 13:11340-50. [DOI: 10.1039/c0cp02470h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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18
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The Use of the “+ U” Correction in Describing Defect States at Metal Oxide Surfaces: Oxygen Vacancies on CeO 2 and TiO 2, and Li-doping of MgO. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2009. [DOI: 10.1380/ejssnt.2009.389] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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19
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Grau-Crespo R, Hernández NC, Sanz JF, de Leeuw NH. Redox properties of gold-substituted zirconia surfaces. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b812245h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Cheng H, Selloni A. Energetics and diffusion of intrinsic surface and subsurface defects on anatase TiO[sub 2](101). J Chem Phys 2009; 131:054703. [DOI: 10.1063/1.3194301] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Shu DJ, Ge ST, Wang M, Ming NB. Interplay between external strain and oxygen vacancies on a rutile TiO2(110) Surface. PHYSICAL REVIEW LETTERS 2008; 101:116102. [PMID: 18851302 DOI: 10.1103/physrevlett.101.116102] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 07/09/2008] [Indexed: 05/26/2023]
Abstract
Comprehensive first-principle calculations on strained rutile TiO2(110) indicate that the formation energy of different types of oxygen vacancies depends on the external strain. For the unstrained state, the energetically favorable oxygen vacancy (EFOV) appears on the bridging site of the first layer; when 3% tensile strain along [11[over ]0] is applied, EFOV moves to the in-plane site, while 2% compressive strain along either [001] or [11[over ]0] shifts EFOV to the subbridging site. We therefore suggest that the distribution of oxygen vacancies can be engineered by external strain, which may help to improve the applications of a TiO2 surface where oxygen vacancy plays an important role.
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Affiliation(s)
- Da-Jun Shu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
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22
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Graciani J, Nambu A, Evans J, Rodriguez JA, Sanz JF. Au ↔ N Synergy and N-Doping of Metal Oxide-Based Photocatalysts. J Am Chem Soc 2008; 130:12056-63. [DOI: 10.1021/ja802861u] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jesús Graciani
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, E-41012, Sevilla, Spain, Chemistry Department, Brookhaven National Laboratory, Upton, New York, United States of America, and Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1020 A, Venezuela
| | - Akira Nambu
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, E-41012, Sevilla, Spain, Chemistry Department, Brookhaven National Laboratory, Upton, New York, United States of America, and Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1020 A, Venezuela
| | - Jaime Evans
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, E-41012, Sevilla, Spain, Chemistry Department, Brookhaven National Laboratory, Upton, New York, United States of America, and Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1020 A, Venezuela
| | - José A. Rodriguez
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, E-41012, Sevilla, Spain, Chemistry Department, Brookhaven National Laboratory, Upton, New York, United States of America, and Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1020 A, Venezuela
| | - Javier Fdez. Sanz
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, E-41012, Sevilla, Spain, Chemistry Department, Brookhaven National Laboratory, Upton, New York, United States of America, and Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1020 A, Venezuela
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Cui X, Wang B, Wang Z, Huang T, Zhao Y, Yang J, Hou JG. Formation and diffusion of oxygen-vacancy pairs on TiO2(110)-(1×1). J Chem Phys 2008; 129:044703. [DOI: 10.1063/1.2955448] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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24
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Zhang Z, Ge Q, Li SC, Kay BD, White JM, Dohnálek Z. Imaging intrinsic diffusion of bridge-bonded oxygen vacancies on TiO2(110). PHYSICAL REVIEW LETTERS 2007; 99:126105. [PMID: 17930526 DOI: 10.1103/physrevlett.99.126105] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Indexed: 05/25/2023]
Abstract
We report the first measurements and calculations of the intrinsic mobility of bridge-bonded oxygen (BBO) vacancies on a rutile TiO2(110). The sequences of isothermal (340-420 K) scanning tunneling microscope images show that BBO vacancies migrate along BBO rows. The hopping rate increases exponentially with increasing temperature with an experimental activation energy of 1.15 eV. Density functional theory calculations are in very good agreement giving an energy barrier for hopping of 1.03 eV. Both theory and experiment indicate repulsive interactions between vacancies on a given BBO row.
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Affiliation(s)
- Zhenrong Zhang
- Pacific Northwest National Laboratory, Fundamental Sciences Directorate, Chemical Sciences Division, Institute for Interfacial Catalysis, Richland, Washington 99352, USA
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25
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San-Miguel MA, Oviedo J, Sanz JF. Influence of temperature on the interaction between Pd clusters and the TiO2 (110) surface. PHYSICAL REVIEW LETTERS 2007; 99:066102. [PMID: 17930842 DOI: 10.1103/physrevlett.99.066102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Indexed: 05/25/2023]
Abstract
The behavior of a Pd nanocluster on the rutile TiO2 (110) surface has been analyzed by extensive first principles molecular dynamics simulations between 100 K and 1073 K. Calculations predict a steep change in the morphological and electronic cluster structure around 800 K in excellent agreement with previous experimental evidence. At low temperature, the cluster geometry is mainly controlled by the substrate structure; however, upon the transition temperature, the cluster-substrate interaction decreases appreciably, and the cluster adopts a geometry more stable in vacuum and becomes metallic. These results illustrate at an atomistic level the influence of temperature on the geometrical and electronic properties of oxide-supported clusters.
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Affiliation(s)
- M A San-Miguel
- Physical Chemistry Department, Faculty of Chemistry, University of Sevilla, c/o Professor García González, 1. 41012, Sevilla, Spain.
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26
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San Miguel MA, Oviedo J, Sanz JF. Ba Adsorption on the Stoichiometric and Defective TiO2 (110) Surface from First-Principles Calculations. J Phys Chem B 2006; 110:19552-6. [PMID: 17004818 DOI: 10.1021/jp063735k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A theoretical study on Ba adsorption on the rutile TiO(2) (110) surface has been carried out by means of plane-wave, plane augmented waves potential, density functional theory calculations. A model consisting on a (4 x 1) unit cell, which corresponds to coverage of 0.125 monolayer (ML), has been used and several potential adsorption sites on the stoichiometric surface have been tried. It has been found that the most stable site is with the Ba atom in a position where it is bound to two bridging oxygen atoms and an in-plane oxygen atom forming equivalent bonds (OB site). The adsorption energy is 0.71 eV referred to the formation of Ba bulk and is about 0.3 eV more stable than other adsorption sites. The Ba-surface interaction produces some surface relaxation in all cases. The OB site is stable at moderate temperatures; however, after extensive molecular dynamic calculations it is found that atoms diffuse on the surface by means of a jumping mechanism among several stable positions. The presence of bridging oxygen vacancies does not alter significantly this picture since the adsorption close to defects is not energetically favorable and the atoms tend to move away from vacancies. A strong covalent character has been found in the nature of the bonding, which contrasts with previous suggestions of the existence of Ba(2+) species on the surface. When the coverage is increased to 0.25 ML by adding a Ba atom to the supercell, there is a significant repulsion between Ba atoms that move away from each other to occupy OB sites. Thus, the adsorption energy values per atom diminish. For the stoichiometric surface two equivalent adsorption patterns are found, whereas only one is found for the defective surface.
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Affiliation(s)
- M A San Miguel
- Departamento de Química Física, Facultad de Química, Universidad de Sevilla, c/ Profesor García Gonzalez, 2, 41012 Sevilla, Spain.
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27
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Nambu A, Graciani J, Rodriguez JA, Wu Q, Fujita E, Sanz JF. N doping of TiO2(110): Photoemission and density-functional studies. J Chem Phys 2006; 125:094706. [PMID: 16965104 DOI: 10.1063/1.2345062] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electronic properties of N-doped rutile TiO2(110) have been investigated using synchrotron-based photoemission and density-functional calculations. The doping via N2+ ion bombardment leads to the implantation of N atoms (approximately 5% saturation concentration) that coexist with O vacancies. Ti 2p core level spectra show the formation of Ti3+ and a second partially reduced Ti species with oxidation states between +4 and +3. The valence region of the TiO(2-x)N(y)(110) systems exhibits a broad peak for Ti3+ near the Fermi level and N-induced features above the O 2p valence band that shift the edge up by approximately 0.5 eV. The magnitude of this shift is consistent with the "redshift" observed in the ultraviolet spectrum of N-doped TiO2. The experimental and theoretical results show the existence of attractive interactions between the dopant and O vacancies. First, the presence of N embedded in the surface layer reduces the formation energy of O vacancies. Second, the existence of O vacancies stabilizes the N impurities with respect to N2(g) formation. When oxygen vacancies and N impurities are together there is an electron transfer from the higher energy 3d band of Ti3+ to the lower energy 2p band of the N(2-) impurities.
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Affiliation(s)
- A Nambu
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Hameeuw KJ, Cantele G, Ninno D, Trani F, Iadonisi G. The rutile TiO2 (110) surface: Obtaining converged structural properties from first-principles calculations. J Chem Phys 2006; 124:024708. [PMID: 16422627 DOI: 10.1063/1.2136158] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the effects of constraining the motion of atoms in finite slabs used to simulate the rutile TiO2 (110) surface in first-principles calculations. We show that an appropriate choice of fixing atoms in a slab eliminates spurious effects due to the finite size of the slabs, leading to a considerable improvement in the simulation of the (110) surface. The method thus allows for a systematic improvement in convergence in calculating both geometrical and electronic properties. The advantages of this approach are illustrated by presenting the first theoretical results on the displacement of the surface atoms in agreement with experiment.
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Affiliation(s)
- K J Hameeuw
- Coherentia CNR-INFM and Università di Napoli Federico II, Dipartimento di Scienze Fisiche, Complesso Universitario Monte Sant' Angelo, Via Cintia, I-80126 Napoli, Italy.
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Oviedo J, Sanz JF. N2O Decomposition on TiO2 (110) from Dynamic First-Principles Calculations. J Phys Chem B 2005; 109:16223-6. [PMID: 16853062 DOI: 10.1021/jp053652o] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have carried out a systematic study of N(2)O dissociation on a TiO(2) (110) surface by means of plane-wave pseudopotential density-functional theory calculations. We have made use of both static and dynamic calculations in order to elucidate N(2)O decomposition mechanisms. We find that dissociation is not favorable on the stoichiometric surface. On the other hand, the presence of oxygen bridging vacancies make the N(2)O decomposition possible. The role of the defective surface is to provide electrons to the adsorbed molecule. We find two channels for decomposition, depending on whether the molecule is adsorbed with the O or the N end of the molecule on a vacancy. The first case is energetically downhill and proceeds spontaneously, leading to N(2) ejection from the surface and vacancy oxidation. The second case relies on the formation of an intermediate bridging configuration of the adsorbed molecule and is hindered by a small energy barrier. In this case, molecule breaking produces N(2) in the gas phase and leaves oxygen adatoms on the surface. We relate our results to recent experimental findings.
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