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Adamsen KC, Petrik NG, Dononelli W, Kimmel GA, Xu T, Li Z, Lammich L, Hammer B, Lauritsen JV, Wendt S. Origin of hydroxyl pair formation on reduced anatase TiO 2(101). Phys Chem Chem Phys 2023; 25:13645-13653. [PMID: 37145025 DOI: 10.1039/d3cp01051a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The interaction of water with metal oxide surfaces is of key importance to several research fields and applications. Because of its ability to photo-catalyze water splitting, reducible anatase TiO2 (a-TiO2) is of particular interest. Here, we combine experiments and theory to study the dissociation of water on bulk-reduced a-TiO2(101). Following large water exposures at room temperature, point-like protrusions appear on the a-TiO2(101) surface, as shown by scanning tunneling microscopy (STM). These protrusions originate from hydroxyl pairs, consisting of terminal and bridging OH groups, OHt/OHb, as revealed by infrared reflection absorption spectroscopy (IRRAS) and valence band experiments. Utilizing density functional theory (DFT) calculations, we offer a comprehensive model of the water/a-TiO2(101) interaction. This model also explains why the hydroxyl pairs are thermally stable up to ∼480 K.
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Affiliation(s)
- Kræn C Adamsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Nikolay G Petrik
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
| | - Wilke Dononelli
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
- MAPEX Center for Materials and Processes, Bremen Center for Computational Materials Science and Hybrid Materials Interfaces Group, Bremen University, 28359 Bremen, Germany
| | - Greg A Kimmel
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
| | - Tao Xu
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Zheshen Li
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Lutz Lammich
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark.
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Bjørk Hammer
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jeppe V Lauritsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Stefan Wendt
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark.
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2
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Ma R, O'Connor CR, Collinge G, Allec SI, Lee MS, Dohnálek Z. The Role of Surface Hydroxyls in the Mobility of Carboxylates on Surfaces: Dynamics of Acetate on Anatase TiO 2(101). J Phys Chem Lett 2023; 14:2542-2550. [PMID: 36877161 DOI: 10.1021/acs.jpclett.3c00175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The dynamics of reactive intermediates are important in catalysis for understanding transient species, which can drive reactivity and the transport of species to reaction centers. In particular, the interplay between surface-bound carboxylic acids and carboxylates is important for numerous chemical transformations, including CO2 hydrogenation and ketonization. Here, we investigate the dynamics of acetic acid on anatase TiO2(101) using scanning tunneling microscopy experiments and density functional theory calculations. We demonstrate the concomitant diffusion of bidentate acetate and a bridging hydroxyl and provide evidence for the transient formation of molecular monodentate acetic acid. The diffusion rate is strongly dependent on the position of hydroxyl and adjacent acetate(s). A facile three-step diffusion process is proposed consisting of acetate and hydroxyl recombination, acetic acid rotation, and acetic acid dissociation. This study clearly demonstrates that the dynamics of bidentate acetate could be important in forming monodentate species, which are proposed to drive selective ketonization.
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Affiliation(s)
- Runze Ma
- Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Christopher R O'Connor
- Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Gregory Collinge
- Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Sarah I Allec
- Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Mal-Soon Lee
- Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Zdenek Dohnálek
- Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99163, United States
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3
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Wang Y, Du L, Guan H, Hao L, Hu Y, Du H. Changing the reaction pathway in TiO 2 photocatalytic dehalogenation of halogenated aromatic pollutants by surface hydroxyl regulation. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130088. [PMID: 36206712 DOI: 10.1016/j.jhazmat.2022.130088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/18/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Understanding the photocatalytic reductive dehalogenation mechanism of halogenated aromatic pollutants is of great research value. However, the proton source in the photocatalytic dehalogenation process of representative halogenated aromatic pollutants by TiO2 is not clear. In this study, the TiO2 surface was modified by hydrochloric acid, sodium hydroxide, and sodium fluoride to obtain TiO2 samples with different hydroxyl groups. It was found that the hydroxyl groups on the surface of TiO2 affects the sequence of proton and electron transfer in dehalogenation. The abundance of hydroxyl groups on the surface of TiO2 can accelerate the reductive dehalogenation process of representative halogenated aromatic pollutants. The kinetic solvent isotope effect was used to study the proton-coupled electron transfer process in the reaction. It shows that the enriching of protons on TiO2 bridging oxygen (bridging hydroxyl groups) is conducive to the rapid step of protonation of the reactant, and subsequent proton and electron transfer. On the contrary, the bridging hydroxyl groups can be removed by reacting with strongly basic sodium hydroxide and sodium ions can occupy the bridging oxygen. The substitution of bridging oxygen by fluorine ions can also lead to the destruction of bridge hydroxyl groups. Significantly, the absence of bridging hydroxyl groups on titanium dioxide will lead to the dehalogenation of representative halogenated aromatic pollutants initiated by electron transfer. This study is helpful to understand dehalogenation reaction paths catalyzed by TiO2.
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Affiliation(s)
- Yuanyuan Wang
- College of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, PR China.
| | - Lang Du
- College of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, PR China
| | - Hangmin Guan
- College of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, PR China
| | - Lingyun Hao
- College of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, PR China
| | - Yingfei Hu
- College of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, PR China.
| | - Hongxiu Du
- College of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, PR China
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4
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Zhong Y, Wang R, Chen J, Duan C, Huang Z, Yu S, Guo H, Zhou Y. Surface-Terminated Hydroxyl Groups for Deciphering the Facet-Dependent Photocatalysis of Anatase TiO 2. ACS APPLIED MATERIALS & INTERFACES 2022; 14:17601-17609. [PMID: 35380775 DOI: 10.1021/acsami.2c04302] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding the relation between a crystal facet and photocatalytic performance is of great importance for the development of effective catalysts. In this work, we focus on anatase TiO2 with controllable exposed facets toward photocatalytic hydrogen evolution by water splitting. By combining temperature-programmed desorption (TPD) and diffuse reflectance infrared spectroscopy (DRIFTS), we obtain that the adsorption of hydroxyl groups and the photo-driven breaking of hydroxyl groups depend strongly on the exposed facets. As a result, the higher catalytic hydrogen evolution activity of TiO2 enclosed with (101) facets than that of (001) facets should be ascribed to the more favorable depletion of hydroxyl groups. Moreover, graphene quantum dots (GQDs) with rich surface functional groups are deliberately deposited on the TiO2 surface. The determination of the states and dynamics of surface hydroxyl groups suggests that GQDs facilitate the reaction of hydroxyl groups on (001)TiO2, thus leading to the activity enhancement. By contrast, the already active (101)TiO2 become apparently less efficient after GQD deposition due to the restricted reaction of hydroxyl groups. Overall, our findings not only provide a unique guidance for understanding the crystal-plane-dependent photocatalysis but also present a powerful approach by which to tailor the photocatalytic performance.
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Affiliation(s)
- Yunqian Zhong
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Rui Wang
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Jiahao Chen
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Chao Duan
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Zhengyue Huang
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Shan Yu
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Heng Guo
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
| | - Ying Zhou
- Institute of Carbon Neutrality & School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan 610500, China
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
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Tanner AJ, Kerr R, Fielding HH, Thornton G. Chemical Modification of Polaronic States in Anatase TiO 2(101). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:14348-14355. [PMID: 34267854 PMCID: PMC8273885 DOI: 10.1021/acs.jpcc.1c03684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/02/2021] [Indexed: 06/13/2023]
Abstract
Two polymorphs of TiO2, anatase and rutile, are employed in photocatalytic applications. It is broadly accepted that anatase is the more catalytically active and subsequently finds wider commercial use. In this work, we focus on the Ti3+ polaronic states of anatase TiO2(101), which lie at ∼1.0 eV binding energy and are known to increase catalytic performance. Using UV-photoemission and two-photon photoemission spectroscopies, we demonstrate the capability to tune the excited state resonance of polarons by controlling the chemical environment. Anatase TiO2(101) contains subsurface polarons which undergo sub-band-gap photoexcitation to states ∼2.0 eV above the Fermi level. Formic acid adsorption dramatically influences the polaronic states, increasing the binding energy by ∼0.3 eV. Moreover, the photoexcitation oscillator strength changes significantly, resonating with states ∼3.0 eV above the Fermi level. We show that this behavior is likely due to the surface migration of subsurface oxygen vacancies.
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Affiliation(s)
- Alex J. Tanner
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Robin Kerr
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Helen H. Fielding
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Geoff Thornton
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
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