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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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2
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Malik AS, Fredin LA. Untangling product selectivity on clean low index rutile TiO 2 surfaces using first-principles calculations. Phys Chem Chem Phys 2023; 25:2203-2211. [PMID: 36594450 DOI: 10.1039/d2cp04939b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Computational modeling of metal oxide surfaces provides an important tool to help untangle complex spectroscopy and measured catalytic reactivity. There are many material properties that make rational catalytic design challenging, and computational methods provide a way to evaluate possible structural factors, like surface structure, individually. The mechanism of water oxidation or oxygen evolution is well studied on some anatase surfaces and the rutile TiO2 (110) surface but has not yet been mapped on other low-index Miller rutile surfaces that are present in most experimental nano-titania catalysts. Here first principles calculations provide new insights into water oxidation mechanisms and reactivity of the most common low-index Miller facets of rutile TiO2. The reactivity of three surfaces, (101), (010), and (001), are explored for the first time and the product selectivity of multistep electron transfer on each surface is compared to the well-studied (110) surface. Density functional theory shows that a peroxo, O(p), intermediate is more favorable for water oxidation on all facets. The ˙OH radical formation is favored on the (001) facet resulting in a high overpotential for oxygen evolution reaction (OER). The (101) and (110) facets have low overpotentials, ∼0.3 V, and favor two-electron proton-coupled electron transfer to produce H2O2. The only facet that prefers direct OER is (001), leading to O2 evolution in a four-electron process with an overpotential of 0.53 V. A volcano plot predicts the selectivity and activity of low-index Miller facets of rutile TiO2, revealing the high activity of the peroxo OER mechanism on the (010) facet.
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Affiliation(s)
- Anum Shahid Malik
- Department of Chemistry, Lehigh University, Bethlehem, PA 18015, USA.
| | - Lisa A Fredin
- Department of Chemistry, Lehigh University, Bethlehem, PA 18015, USA.
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3
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Anodic electrocatalytic behavior of graphite supported TiO2 towards the generation of hydroxyl radicals. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.141303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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4
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Li H, Shang H, Jiang F, Zhu X, Ruan Q, Zhang L, Wang J. Plasmonic O 2 dissociation and spillover expedite selective oxidation of primary C-H bonds. Chem Sci 2021; 12:15308-15317. [PMID: 34976351 PMCID: PMC8635223 DOI: 10.1039/d1sc04632b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/26/2021] [Indexed: 01/01/2023] Open
Abstract
Manipulating O2 activation via nanosynthetic chemistry is critical in many oxidation reactions central to environmental remediation and chemical synthesis. Based on a carefully designed plasmonic Ru/TiO2−x catalyst, we first report a room-temperature O2 dissociation and spillover mechanism that expedites the “dream reaction” of selective primary C–H bond activation. Under visible light, surface plasmons excited in the negatively charged Ru nanoparticles decay into hot electrons, triggering spontaneous O2 dissociation to reactive atomic ˙O. Acceptor-like oxygen vacancies confined at the Ru–TiO2 interface free Ru from oxygen-poisoning by kinetically boosting the spillover of ˙O from Ru to TiO2. Evidenced by an exclusive isotopic O-transfer from 18O2 to oxygenated products, ˙O displays a synergistic action with native ˙O2− on TiO2 that oxidizes toluene and related alkyl aromatics to aromatic acids with extremely high selectivity. We believe the intelligent catalyst design for desirable O2 activation will contribute viable routes for synthesizing industrially important organic compounds. Room-temperature O2 dissociation and spillover, as driven by plasmonic Ru on oxygen-deficient TiO2, expedite the selective oxidation of primary C–H bonds in alkyl aromatics for synthesizing industrially important organic compounds.![]()
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Affiliation(s)
- Hao Li
- Institute of Environmental Engineering, ETH Zürich Zürich 8093 Switzerland .,Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology Dübendorf 8600 Switzerland
| | - Huan Shang
- Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry, Central China Normal University Wuhan 430079 China
| | - Fuze Jiang
- Institute of Environmental Engineering, ETH Zürich Zürich 8093 Switzerland .,Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology Dübendorf 8600 Switzerland
| | - Xingzhong Zhu
- College of Science, Nanjing University of Aeronautics and Astronautics Nanjing 210016 China
| | - Qifeng Ruan
- Engineering Product Development, Singapore University of Technology and Design Singapore 487372 Singapore
| | - Lizhi Zhang
- Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry, Central China Normal University Wuhan 430079 China
| | - Jing Wang
- Institute of Environmental Engineering, ETH Zürich Zürich 8093 Switzerland .,Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology Dübendorf 8600 Switzerland
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5
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Zhang W, Gao M, Miao F, Wu X, Wang S, Wang X. A permeable electrochemical reactive barrier for underground water remediation using TiO 2/graphite composites as heterogeneous electrocatalysts without releasing of chemical substances. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126318. [PMID: 34118548 DOI: 10.1016/j.jhazmat.2021.126318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
Permeable reactive barriers (PRBs) are well-studied and widely-applied technologies in underground water remediation. However, the releasing of chemical substances cannot be avoided during the PRBs operation. In this study, a novel permeable electrochemical reactive barrier (PERB) was fabricated for underground water remediation using a TiO2/graphite composite (TiO2/C) as the heterogeneous electrocatalyst. TiO2/C performed an electro-Fenton-like reaction on cathode and an anodic oxidation on anode respectively, along with the variety of the TiO2 lattice. The performance of this PERB system was evaluated using tetracycline hydrochloride (TTC) degradation. TTC could be degraded at a low applied potential and a wide range of pH. The degradation rate of about 60% was obtained at the optimized reaction condition: the interelectrode potential difference of 1.2 V, pH 3.0, the anode 10 cm above cathode. The relative position and spacing of the electrodes effected the mass transfer equilibrium of TTC. During the 25-day persistent degradation of TTC, the PERB system shown a perfect stability with rarely leaching of Ti. This work explored the potential for underground water remediation by the electrocatalysis with the goal of establishing a clean and eco-friendly PERB system.
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Affiliation(s)
- Wen Zhang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China
| | - Mingming Gao
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
| | - Fei Miao
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China
| | - Xiaoyan Wu
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China
| | - Shuguang Wang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China
| | - Xinhua Wang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
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6
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Li H, Ai Z, Zhang L. Surface structure-dependent photocatalytic O 2 activation for pollutant removal with bismuth oxyhalides. Chem Commun (Camb) 2020; 56:15282-15296. [PMID: 33165493 DOI: 10.1039/d0cc05449f] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The purification of water and air by semiconductor photocatalysis is a rapidly growing area for academic research and industrial innovation, featured with ambient removal of organic or inorganic pollutants by using solar light as the energy source and atmospheric O2 as the green oxidant. Both charge transfer and energy transfer from excited photocatalysts can overcome the spin-forbidden nature of O2. Layered bismuth oxyhalides are a new group of two-dimensional photocatalysts with an appealing geometric and surface structure that allows the dynamic and selective tuning of O2 activation at the surface molecular level. In this Feature Article, we specifically summarize our recent progress in selective O2 activation by engineering surface structures of bismuth oxyhalides. Then, we demonstrate selective photocatalytic O2 activation of bismuth oxyhalides for environmental control, including water decontamination, volatile organic compound oxidation and nitrogen oxide removal, as well as selective catalytic oxidations. Challenges and opportunities regarding the design of photocatalysts with satisfactory performance for potential environmental control applications are also presented.
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Affiliation(s)
- Hao Li
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China.
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7
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He T, Shao D, Zeng X, Rong S. Harvesting the vibration energy of α-MnO 2 nanostructures for complete catalytic oxidation of carcinogenic airborne formaldehyde at ambient temperature. CHEMOSPHERE 2020; 261:127778. [PMID: 32739692 DOI: 10.1016/j.chemosphere.2020.127778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/13/2020] [Accepted: 07/19/2020] [Indexed: 06/11/2023]
Abstract
Vibration is one of the most prevalent energy sources in natural environment, which can also be harvested and utilized to drive chemical reaction. Herein, mechanical vibration is used for enhancing the catalytic decomposition of formaldehyde at ambient temperature with the assistance of four well-defined morphologies α-MnO2 (nanowire, nanotube, nanorod and nanoflower). In particular, α-MnO2 nanowire exhibits the best catalytic activity, which can completely mineralize formaldehyde into carbon dioxide at ambient temperature by harvesting the vibration energy. To the best of our knowledge, this may be the first report that α-MnO2, as a non-noble metal catalyst, can completely decompose formaldehyde to carbon dioxide at ambient temperature. The characterization results show that α-MnO2 nanowire has a much higher oxygen vacancy concentration than other three catalysts. In addition, thermal effect generated from friction between nanoparticles induced by ultrasonic vibration may enhance its catalytic activity. More importantly, it is the vibration that effectively promotes the activation of O2 adsorbed on the surface oxygen vacancy to produce more , thus increasing the catalytic decomposition performance. The strategy presented herein demonstrates a new approach for efficient use of mechanical vibration to improve catalytic activity of traditional catalysts.
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Affiliation(s)
- Taohong He
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Dadong Shao
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Xiaoshan Zeng
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Shaopeng Rong
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China.
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8
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Sokolović I, Reticcioli M, Čalkovský M, Wagner M, Schmid M, Franchini C, Diebold U, Setvín M. Resolving the adsorption of molecular O 2 on the rutile TiO 2(110) surface by noncontact atomic force microscopy. Proc Natl Acad Sci U S A 2020; 117:14827-14837. [PMID: 32527857 PMCID: PMC7334520 DOI: 10.1073/pnas.1922452117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interaction of molecular oxygen with semiconducting oxide surfaces plays a key role in many technologies. The topic is difficult to approach both by experiment and in theory, mainly due to multiple stable charge states, adsorption configurations, and reaction channels of adsorbed oxygen species. Here we use a combination of noncontact atomic force microscopy (AFM) and density functional theory (DFT) to resolve [Formula: see text] adsorption on the rutile [Formula: see text](110) surface, which presents a longstanding challenge in the surface chemistry of metal oxides. We show that chemically inert AFM tips terminated by an oxygen adatom provide excellent resolution of both the adsorbed species and the oxygen sublattice of the substrate. Adsorbed [Formula: see text] molecules can accept either one or two electron polarons from the surface, forming superoxo or peroxo species. The peroxo state is energetically preferred under any conditions relevant for applications. The possibility of nonintrusive imaging allows us to explain behavior related to electron/hole injection from the tip, interaction with UV light, and the effect of thermal annealing.
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Affiliation(s)
- Igor Sokolović
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Michele Reticcioli
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- Center for Computational Materials Science, University of Vienna, 1090 Vienna, Austria
| | - Martin Čalkovský
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Institute of Physical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic
| | - Margareta Wagner
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Central European Institute of Technology, Brno University of Technology, 612 00 Brno, Czech Republic
| | - Michael Schmid
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Cesare Franchini
- Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- Center for Computational Materials Science, University of Vienna, 1090 Vienna, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Martin Setvín
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria;
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00 Prague 8, Czech Republic
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9
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Ebenhoch C, Kalb J, Lim J, Seewald T, Scheu C, Schmidt-Mende L. Hydrothermally Grown TiO 2 Nanorod Array Memristors with Volatile States. ACS APPLIED MATERIALS & INTERFACES 2020; 12:23363-23369. [PMID: 32321245 DOI: 10.1021/acsami.0c05164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the present study, the memristive characteristics of hydrothermally grown TiO2 nanorod arrays, particularly, the difference in the retention time of the resistance state, are investigated in dependence of the array growth temperature. A volatile behavior is observed and related to a redistribution of oxygen vacancies over time. It is shown that the retention time increases for increasing array growth temperatures from several seconds up to 20 min. The relaxation behavior is also seen in the current-voltage characteristics, which do not show the common unipolar, bipolar, or complementary switching behavior. Instead, the temporal evolution depends on the duration of the applied voltage and on the nanowire growth temperature. Therefore, electronic measurements are combined with scanning electron and scanning transmission electron microscopy, so that the amount of oxygen defect-rich grain boundaries in the upper part of the nanowires can be linked to the differences in the current-voltage behavior and retention time.
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Affiliation(s)
- Carola Ebenhoch
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Julian Kalb
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Joohyun Lim
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
| | - Tobias Seewald
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Christina Scheu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
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10
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Wu L, Fu C, Huang W. Surface chemistry of TiO 2 connecting thermal catalysis and photocatalysis. Phys Chem Chem Phys 2020; 22:9875-9909. [PMID: 32363360 DOI: 10.1039/c9cp07001j] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chemical reactions catalyzed under heterogeneous conditions have recently expanded rapidly from traditional thermal catalysis to photocatalysis due to the rising concerns about sustainable development of energy and the environment. Adsorption of reactants on catalyst surfaces, subsequent surface reactions, and desorption of products from catalyst surfaces occur in both thermal catalysis and photocatalysis. TiO2 catalysts are widely used in thermal catalytic and photocatalytic reactions. Herein we review recent progress in surface chemistry, thermal catalysis and photocatalysis of TiO2 model catalysts from single crystals to nanocrystals with the aim of examining if the surface chemistry of TiO2 can bridge the fundamental understanding between thermal catalysis and photocatalysis. Following a brief introduction, the structures of major facets exposed on TiO2 catalysts, including surface reconstructions and defects, as well as the electronic structure and charge properties, are firstly summarized; then the recent progress in adsorption, thermal chemistry and photochemistry of small molecules on TiO2 single crystals and nanocrystals is comprehensively reviewed, focusing on manifesting the structure-(photo)activity relations and the commonalities/differences between thermal catalysis and photocatalysis; and finally concluding remarks and perspectives are given.
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Affiliation(s)
- Longxia Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China.
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11
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Guo Q, Zhou C, Ma Z, Yang X. Fundamentals of TiO 2 Photocatalysis: Concepts, Mechanisms, and Challenges. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901997. [PMID: 31423680 DOI: 10.1002/adma.201901997] [Citation(s) in RCA: 422] [Impact Index Per Article: 84.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/23/2019] [Indexed: 05/27/2023]
Abstract
Photocatalysis has been widely applied in various areas, such as solar cells, water splitting, and pollutant degradation. Therefore, the photochemical mechanisms and basic principles of photocatalysis, especially TiO2 photocatalysis, have been extensively investigated by various surface science methods in the last decade, aiming to provide important information for TiO2 photocatalysis under real environmental conditions. Recent progress that provides fundamental insights into TiO2 photocatalysis at a molecular level is highlighted. Insights into the structures of TiO2 and the basic principles of TiO2 photocatalysis are discussed first, which provides the basic concepts of TiO2 photocatalysis. Following this, details of the photochemistry of three important molecules (oxygen, water, methanol) on the model TiO2 surfaces are presented, in an attempt to unravel the relationship between charge/energy transfer and bond breaking/forming in TiO2 photocatalysis. Lastly, challenges and opportunities of the mechanistic studies of TiO2 photocatalysis at the molecular level are discussed briefly, as well as possible photocatalysis models.
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Affiliation(s)
- Qing Guo
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, China
- Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen, 518055, China
| | - Chuanyao Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, China
| | - Zhibo Ma
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, China
- Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen, 518055, China
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12
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Li H, Shang H, Li Y, Cao X, Yang Z, Ai Z, Zhang L. Interfacial Charging-Decharging Strategy for Efficient and Selective Aerobic NO Oxidation on Oxygen Vacancy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6964-6971. [PMID: 31084027 DOI: 10.1021/acs.est.9b01287] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Intelligent defect engineering to harness surface molecular processes is at the core of selective oxidation catalysis. Here, we demonstrate that the two-electron-trapped oxygen vacancy (VO) of BiOCl, a prototypical F center (VŐ''), is a superb site to confine O2 toward efficient and selective NO oxidation to nitrate. Stimulated by solar light, VŐ'' accomplishes NO oxidation through a two-electron charging (VŐ'' + O2 → VŐ''-O22-) and subsequent one-electron decharging process (VŐ''-O22- + NO → VO-NO3- + e-). The back-donated electron is retrapped by VO to produce a new single-electron-trapped VO (VO'), simultaneously triggering a second round of NO oxidation (VO'-O2 + NO → VO-NO3-). This unprecedented interfacial charging-decharging scheme alters the peroxide-associated NO oxidation selectivity from NO2 to NO3- with a high efficiency and thus hold great promise for the treatment of risky NO x species in indoor air.
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Affiliation(s)
- Hao Li
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry , Central China Normal University , Wuhan 430079 , P. R. China
| | - Huan Shang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry , Central China Normal University , Wuhan 430079 , P. R. China
| | - Yuhan Li
- Chongqing Key Laboratory of Catalysis and New Environmental Materials, Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, College of Environment and Resources , Chongqing Technology and Business University , Chongqing 400067 , China
| | - Xuemei Cao
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry , Central China Normal University , Wuhan 430079 , P. R. China
| | - Zhiping Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry , Central China Normal University , Wuhan 430079 , P. R. China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry , Central China Normal University , Wuhan 430079 , P. R. China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry, College of Chemistry , Central China Normal University , Wuhan 430079 , P. R. China
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13
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Li H, Shang H, Cao X, Yang Z, Ai Z, Zhang L. Oxygen Vacancies Mediated Complete Visible Light NO Oxidation via Side-On Bridging Superoxide Radicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:8659-8665. [PMID: 29962202 DOI: 10.1021/acs.est.8b01849] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
It is of a great challenge to seek for semiconductor photocatalysts with prominent reactivity to remove kinetically inert dilute NO without NO2 emission. In this study, complete visible light NO oxidation mediated by O2 is achieved over a defect-engineered BiOCl with selectivity exceeding 99%. Well-designed oxygen vacancies on the prototypical (001) surface of BiOCl favored the possible formation of geometric-favorable superoxide radicals (•O2-) in a side-on bridging mode under ambient condition, which thermodynamically suppressed the terminal end-on •O2- associated NO2 emission in case of higher temperatures, and thus selectively oxidized NO to nitrate. These findings can help us to understand the intriguing surface chemistry of photocatalytic NO oxidation and design highly efficient NO x removal systems.
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Affiliation(s)
- Hao Li
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry , College of Chemistry, Central China Normal University , Wuhan 430079 , P. R. China
| | - Huan Shang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry , College of Chemistry, Central China Normal University , Wuhan 430079 , P. R. China
| | - Xuemei Cao
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry , College of Chemistry, Central China Normal University , Wuhan 430079 , P. R. China
| | - Zhiping Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry , College of Chemistry, Central China Normal University , Wuhan 430079 , P. R. China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry , College of Chemistry, Central China Normal University , Wuhan 430079 , P. R. China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Applied & Environmental Chemistry , College of Chemistry, Central China Normal University , Wuhan 430079 , P. R. China
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14
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Guo Q, Zhou C, Ma Z, Ren Z, Fan H, Yang X. Elementary photocatalytic chemistry on TiO2surfaces. Chem Soc Rev 2016; 45:3701-30. [DOI: 10.1039/c5cs00448a] [Citation(s) in RCA: 250] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this article, we review the recent advances in the photoreactions of small molecules with model TiO2surfaces, and propose a photocatalytical model based on nonadiabatic dynamics and ground state surface reactions.
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Affiliation(s)
- Qing Guo
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Chuanyao Zhou
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Zhibo Ma
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Zefeng Ren
- International Center for Quantum Materials and School of Physics
- Peking University
- Beijing
- P. R. China
- Collaborative Innovation Center of Quantum Matter
| | - Hongjun Fan
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
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15
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Tan SJ, Wang B. Active Sites for Adsorption and Reaction of Molecules on Rutile TiO2(110) and Anatase TiO2(001) Surfaces. CHINESE J CHEM PHYS 2015. [DOI: 10.1063/1674-0068/28/cjcp1506129] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Xu C, Yang W, Guo Q, Dai D, Chen M, Yang X. Suppression of Photoinduced BBO Defects Generation on TiO2(110) by Water. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/06/646-650] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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17
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Dholabhai PP, Yu HG. Electronic structure and quantum dynamics of photoinitiated dissociation of O2 on rutile TiO2 nanocluster. J Chem Phys 2013; 138:194705. [DOI: 10.1063/1.4805000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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18
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Pang CL, Lindsay R, Thornton G. Structure of clean and adsorbate-covered single-crystal rutile TiO2 surfaces. Chem Rev 2013; 113:3887-948. [PMID: 23676004 DOI: 10.1021/cr300409r] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Chi Lun Pang
- London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
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19
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Guo Q, Xu C, Ren Z, Yang W, Ma Z, Dai D, Fan H, Minton TK, Yang X. Stepwise Photocatalytic Dissociation of Methanol and Water on TiO2(110). J Am Chem Soc 2012; 134:13366-73. [DOI: 10.1021/ja304049x] [Citation(s) in RCA: 212] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Qing Guo
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Chenbiao Xu
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Zefeng Ren
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Wenshao Yang
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Zhibo Ma
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Dongxu Dai
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Hongjun Fan
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Timothy K. Minton
- Department of Chemistry and
Biochemistry, Montana State University,
Bozeman, Montana 59717, United States
| | - Xueming Yang
- State Key Laboratory of Molecular
Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
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20
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Aschauer U, Selloni A. Structure of the rutile TiO2(011) surface in an aqueous environment. PHYSICAL REVIEW LETTERS 2011; 106:166102. [PMID: 21599389 DOI: 10.1103/physrevlett.106.166102] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Indexed: 05/21/2023]
Abstract
First principles simulations are carried out to investigate the structure and stability of the rutile TiO2(011) surface in contact with liquid water. Whereas this surface exhibits a (2×1) reconstruction in vacuo, our results show that the interaction with water leads to an inversion of the stabilities of the reconstructed and unreconstructed surfaces. This indicates that surface structures determined in vacuo or at low water coverages are not generally representative of those occurring in the aqueous environments typical of most photocatalytic applications of TiO2.
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Affiliation(s)
- U Aschauer
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, USA
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21
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Tan S, Ji Y, Zhao Y, Zhao A, Wang B, Yang J, Hou J. Molecular Oxygen Adsorption Behaviors on the Rutile TiO2(110)-1×1 Surface: An in Situ Study with Low-Temperature Scanning Tunneling Microscopy. J Am Chem Soc 2011; 133:2002-9. [DOI: 10.1021/ja110375n] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shijing Tan
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Yongfei Ji
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Yan Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Aidi Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Bing Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - J.G. Hou
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China
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22
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Scheiber P, Riss A, Schmid M, Varga P, Diebold U. Observation and destruction of an elusive adsorbate with STM: O₂/TiO₂(110). PHYSICAL REVIEW LETTERS 2010; 105:216101. [PMID: 21231324 DOI: 10.1103/physrevlett.105.216101] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Indexed: 05/30/2023]
Abstract
When a slightly defective rutile TiO₂(110) surface is exposed to O₂at elevated temperatures, the molecule dissociates at defects, filling O vacancies (V(O)) and creating O adatoms (O(ad)) on Ti(5c) rows. The adsorption of molecular O₂ at low temperatures has remained controversial. Low-temperature scanning tunneling microscopy of O₂, dosed on TiO₂(110) at a sample temperature of ≈100 K and imaged at 17 K, shows a molecular precursor at V(O) as a faint change in contrast. The adsorbed O₂ easily dissociates during the STM measurements, and the formation of O(ad)'s at both sides of the original V(O) is observed.
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Affiliation(s)
- Philipp Scheiber
- Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
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23
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Aschauer U, Chen J, Selloni A. Peroxide and superoxide states of adsorbed O(2) on anatase TiO(2) (101) with subsurface defects. Phys Chem Chem Phys 2010; 12:12956-60. [PMID: 20820549 DOI: 10.1039/c0cp00116c] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density Functional Theory (DFT) calculations within the Generalized Gradient Approximation (GGA) and the GGA + U approach are carried out to investigate the adsorption of O(2) on anatase (101) surfaces having subsurface oxygen vacancies. Our results show that O(2) adsorption is strongly enhanced at sites close to the subsurface defect, whereas dissociation is unfavorable at all sites. The adsorption is accompanied by the transfer of the defect electrons to O(2)-derived electronic states in the anatase surface band gap. Peroxide species (O(2)(2-), O-O = 1.48 Å) are stable when the number of adsorbed O(2) molecules is less or equal the number of defects, whereas superoxide species (O(2)(-), O-O = 1.33 Å) become more favorable at coverages exceeding approximately 1.5 O(2) molecules per oxygen vacancy.
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Affiliation(s)
- Ulrich Aschauer
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, NJ 08544, USA.
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24
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López N, Prades JD, Hernández-Ramírez F, Morante JR, Pan J, Mathur S. Bidimensional versus tridimensional oxygen vacancy diffusion in SnO(2-x) under different gas environments. Phys Chem Chem Phys 2010; 12:2401-6. [PMID: 20449353 DOI: 10.1039/b921213b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal oxides present oxygen defects that induce different chemical and physical properties. Experiments performed in SnO(2-x) sensors show that the dynamics of these vacancies are strongly affected by the presence of different gases in the environment. Experimentally, the electrical resistance of individual metal oxide SnO(2-x) nanowires shows modulation: when the environment is oxygen rich long term drifts (hours) are observed indicating extended vacancy dynamics. Instead, if CO is present, drifts disappear in minutes. Density functional theory indicates that changes in resistance follow the extension of reoxidation. For oxygen-poor environments, oxygen vacancy excorporation and healing are confined to the near-surface layer of SnO(2-x) (bidimensional or near-surface diffusion), and completed in short times. Under oxygen-rich conditions, tridimensional diffusion of oxygen vacancies towards the surface takes place at room temperature. In this case, a push-pull mechanism allows bulk-to-surface diffusion and as a consequence resistance drifts are longer and the vacancy quenching is more extensive.
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Affiliation(s)
- N López
- Institute of Chemical Research of Catalonia, ICIQ, Av. Països Catalans 16, 43007 Tarragona, Spain.
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25
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Tilocca A. Models of structure, dynamics and reactivity of bioglasses: a review. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm01081b] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Tilocca A, Cormack AN. Modeling the water-bioglass interface by ab initio molecular dynamics simulations. ACS APPLIED MATERIALS & INTERFACES 2009; 1:1324-1333. [PMID: 20355929 DOI: 10.1021/am900198t] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The hydration of the surface of a highly bioactive silicate glass was modeled using ab initio (Car-Parrinello) molecular dynamics (CPMD) simulations, focusing on the structural and chemical modifications taking place at the glass-water interface immediately after contact and on the way in which they can affect the bioactivity of these materials. The adsorption of a water dimer and trimer on the dry surface was studied first, followed by the extended interface between the glass and liquid water. The CPMD trajectories provide atomistic insight into the initial stages relevant to the biological activity of these materials: following contact of the glass with an aqueous (physiological) medium, the initial enrichment of the surface region in Na+ cations establishes dominant Na+-water interactions at the surface, which allow water molecules to penetrate into the open glass network and start its partial dissolution. The model of a Na/H-exchanged interface shows that Ca2+-water interactions are mainly established after the dominant fraction of Na is leached into the solution. Another critical role of modifier cations was highlighted: they provide the Lewis acidity necessary to neutralize OH(-) produced by water dissociation and protonation of nonbridging oxygen (NBO) surface sites. The CPMD simulations also highlighted an alternative, proton-hopping mechanism by which the same process can take place in the liquid water film. The main features of the bioactive glass surface immediately after contact with an aqueous medium, as emerged from the simulations, are (a) silanol groups formed by either water dissociation at undercoordinated Si sites or direct protonation of NBOs, (b) OH(-) groups generally stabilized by modifier cations and coupled with the protonated NBOs, and (c) small rings, relatively stable and unopened even after exposure to liquid water. The possible role and effect of these sites in the bioactive process are discussed.
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Affiliation(s)
- Antonio Tilocca
- Department of Chemistry, University College London, London, U.K.
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27
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Chrétien S, Metiu H. O2 evolution on a clean partially reduced rutile TiO2(110) surface and on the same surface precovered with Au1 and Au2: the importance of spin conservation. J Chem Phys 2009; 129:074705. [PMID: 19044790 DOI: 10.1063/1.2956506] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
We have used spin-polarized density functional theory (DFT) to study O(2) evolution on a clean partially reduced rutile TiO(2)(110) surface (i.e., a surface having oxygen vacancies) and its interaction with Au(1) or Au(2) cluster adsorbed on it. We assume that the total spin of the electronic wave function is related to the number of unpaired spins (N(s)) and calculate the binding and the activation energies involved in O(2) evolution for fixed values of N(s). In addition to keeping N(s) constant, we assume that reactions in which the N(s) of the reactants differs from that of the products are very slow. The potential energy surfaces obtained in this way depend strongly on N(s). For example, O(2) dissociation at the vacancy site on a clean partially reduced TiO(2)(110) surface is exothermic by 0.85 eV in the triplet state and the highest activation energy in the chain of reactions leading to the O(2) dissociation is 0.67 eV. In the singlet state, O(2) dissociation is endothermic by 0.11 eV and the activation energy leading to dissociation is 1.30 eV. These observations are in qualitative agreement with scanning tunneling microscopy experiment in which O(2) dissociation on a partially reduced rutile TiO(2)(110) surface is observed at temperature as low as 120 K. In contrast, O(2) dissociation is predicted to be endothermic and is prevented by an activation barrier larger than 1 eV in all the previous DFT calculations, in which the DFT program varies N(s) to get the lowest energy state. We find that on a partially reduced rutile TiO(2)(110) with Au(1) and Au(2) preadsorbed on its surface, O(2) dissociates at the vacancy site: One oxygen atom fills the oxygen vacancy and the other becomes available for oxidation chemistry. This means that Au(1) and Au(2) supported on a partially reduced TiO(2)(110) surface is not an oxidation catalyst since the presence of oxygen turns it into a stoichiometric Au(n)/TiO(2)(110) surface. Finally, we find that the evolution of oxygen on Au(1) and Au(2) in the gas phase is very different from the evolution on the same clusters supported on the partially reduced TiO(2)(110) surface. For example, the molecular adsorption of O(2) is favored in the gas phase (except on Au(1) (-) and Au(2) (-) in the quartet state), while the dissociative adsorption is favored by more than 1 eV when Au(1) and Au(2) are supported on the partially reduced TiO(2)(110). Furthermore, the activation energies associated with O(2) dissociation in the gas phase (DeltaE(act)>2.4 eV) are reduced by at least a factor of 2 when the clusters are supported on TiO(2)(110).
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Affiliation(s)
- Steeve Chrétien
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
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28
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Kimmel GA, Petrik NG. Tetraoxygen on reduced TiO2(110): oxygen adsorption and reactions with bridging oxygen vacancies. PHYSICAL REVIEW LETTERS 2008; 100:196102. [PMID: 18518464 DOI: 10.1103/physrevlett.100.196102] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Indexed: 05/26/2023]
Abstract
Oxygen adsorption on reduced TiO2(110) is investigated using temperature programmed desorption and electron-stimulated desorption. At low temperatures, 2 O(2) molecules can be chemisorbed in each oxygen vacancy. These molecules do not desorb upon annealing to 700 K. Instead, for 200 K<T<400 K, the 2 O(2) convert to another species, which has four oxygen atoms, i.e., tetraoxygen, that decomposes at higher temperatures. In contrast, when only 1 O(2) is adsorbed in an oxygen vacancy, the molecule dissociates upon annealing above ~150 K to heal the vacancy in agreement with previous results.
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Affiliation(s)
- Greg A Kimmel
- Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
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29
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Metiu H. Preface to Special Topic: A Survey of Some New Developments in Heterogeneous Catalysis. J Chem Phys 2008; 128:182501. [DOI: 10.1063/1.2894545] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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30
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Di Valentin C. Scanning tunneling microscopy image simulation of the rutile (110) TiO2 surface with hybrid functionals and the localized basis set approach. J Chem Phys 2007; 127:154705. [DOI: 10.1063/1.2790430] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Tilocca A, de Leeuw NH. Ab Initio Molecular Dynamics Study of 45S5 Bioactive Silicate Glass. J Phys Chem B 2006; 110:25810-6. [PMID: 17181225 DOI: 10.1021/jp065146k] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bioglass 45S5, the prototype of bioactive melt-quenched silicate glasses, was modeled by means of Car-Parrinello molecular dynamics (CPMD) simulations. Although long-range structural properties cannot be modeled by using this ab initio approach, the accuracy of CPMD simulations is exploited here to provide insight into the short-range structure and to analyze vibrational and electronic properties of this biomaterial. Detailed structural analysis in the short-range scale provided insight into the local environment of modifier Na and Ca ions: a possible key role of these cations in organizing the glass network by connecting different chains and fragments into specific, rather flexible geometries was proposed. The individual contributions of different species to the vibrational density of states were separated and discussed, allowing the identification of specific features in the vibrational spectrum, such as those related to phosphate groups. The components of the electronic density of states were also analyzed, enabling us to identify correlations between the electronic structure and the structural properties, such as the different bonding character of Si-O bonds involving bridging or nonbridging oxygen atoms.
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Affiliation(s)
- Antonio Tilocca
- Department of Chemistry, University College London, London, United Kingdom.
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32
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Reinhardt D, Krieck S, Meyer S. Special titanium dioxide layers and their electrochemical behaviour. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2006.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Qu ZW, Kroes GJ. Theoretical Study of Adsorption of O(3P) and H2O on the Rutile TiO2(110) Surface. J Phys Chem B 2006; 110:23306-14. [PMID: 17107180 DOI: 10.1021/jp065028x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The adsorption of oxygen atoms O(3P) on both ideal and hydrated rutile TiO(2)(110) surfaces is investigated by periodic density functional theory (DFT) calculations within the revised Perdew-Burke-Ernzerhof (RPBE) generalized gradient approximation and a four Ti-layer slab, with (2 x 1) and (3 x 1) surface unit cells. It is shown that upon adsorption on the TiO(2) surface the spin of the O atom is completely lost, leading to stable surface peroxide species on both in-plane and bridging oxygen sites with O-binding energies of about 1.0-1.5 eV, rather than to the kinetically unstable terminal Ti-O and terminal O-O species with smaller binding energies of 0.1-0.7 eV. Changes in O-atom coverage ratios between 1/3 and 1 molecular layer (ML) and coadsorption of H(2)O have only minor effects on the O-binding energies of the stable peroxide configurations. High O-atom diffusion barriers of about 1 eV are found, suggesting a slow recombination rate of adsorbed O atoms on TiO(2)(110). Our results suggest that the TiOOTi peroxide intermediate experimentally observed in photoelectrolysis of water should be interpreted as a single spinless O adatom on TiO(2) surface rather than as two Ti-O* radicals coupled together.
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Affiliation(s)
- Zheng-Wang Qu
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Post Office Box 9502, 2300 RA Leiden, The Netherlands.
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34
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Tilocca A, Di Valentin C, Selloni A. O2 Interaction and Reactivity on a Model Hydroxylated Rutile(110) Surface. J Phys Chem B 2005; 109:20963-7. [PMID: 16853717 DOI: 10.1021/jp0544181] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently several theoretical studies have examined oxygen adsorption on the clean, reduced TiO2(110) surface. However the photocatalytic behavior of TiO2 and the scavenging ability of oxygen are known to be influenced by the presence of surface hydroxyls. In this paper the chemistry of O2 on the hydroxylated TiO2 surface is investigated by means of first-principles total energy calculations and molecular dynamics (MD) simulations. The MD trajectories show a direct, spontaneous reaction between O2 and the surface hydroxyls, thus supporting the experimental hypothesis that the reaction does not necessarily pass through a chemisorbed O2 state. Following this reaction, the most stable chemisorbed intermediates are found to be peroxide species HO2 and H2O2. Although these intermediates are very stable on the short time scale of MD simulations, the energetics suggests that their further transformation is connected to a new 300 K feature observed in the experimental water temperature programmed desorption (TPD) spectrum. The participation of two less stable intermediate states, involving terminal hydroxyls and/or chemisorbed water plus oxygen adatoms, to the desorption process, is not supported by the total energy calculations. Analysis of the projected density of states, however, suggests the possibility that these intermediates have a role in completing the surface oxidation immediately before desorption.
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Affiliation(s)
- Antonio Tilocca
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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