Site Sensitivity of Interfacial Charge Transfer and Photocatalytic Efficiency in Photocatalysis: Methanol Oxidation on Anatase TiO2 Nanocrystals

Cong Fu; Fei Li; Jiachen Zhang; Dan Li; Kun Qian; Yong Liu; Junwang Tang; Fengtao Fan; Qun Zhang; Xue-Qing Gong; Weixin Huang

doi:10.1002/anie.202014037

Site Sensitivity of Interfacial Charge Transfer and Photocatalytic Efficiency in Photocatalysis: Methanol Oxidation on Anatase TiO₂ Nanocrystals

Angew Chem Int Ed Engl. 2021 Mar 8;60(11):6160-6169. doi: 10.1002/anie.202014037. Epub 2021 Feb 16.

Authors

Cong Fu¹, Fei Li², Jiachen Zhang³, Dan Li¹, Kun Qian¹, Yong Liu⁴, Junwang Tang⁵, Fengtao Fan^{4

6}, Qun Zhang³, Xue-Qing Gong², Weixin Huang^{1

6}

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Heifei, 230026, P. R. China.
² Key Laboratory for Advanced Materials, Centre for Computational Chemistry and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai, 200237, P. R. China.
³ Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Heifei, 230026, P. R. China.
⁴ State Key Laboratory of Catalysis, Dalian Institute of, Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
⁵ Department of Chemical Engineering, University College London, London, WC1E 7JE, UK.
⁶ Dalian National Laboratory for Clean Energy, Dalian, 116023, P. R. China.

PMID: 33289198
DOI: 10.1002/anie.202014037

Abstract

Photocatalytic oxidation of methanol on various anatase TiO₂ nanocrystals was studied by in situ and time-resolved characterizations and DFT calculations. Surface site and resulting surface adsorbates affect the surface band bending/bulk-to-surface charge migration processes and interfacial electronic structure/interfacial charge transfer processes. TiO₂ nanocrystals predominantly enclosed by the {001} facets expose a high density of reactive fourfold-coordinated Ti sites (Ti_4c ) at which CH₃ OH molecules dissociate to form the CH₃ O adsorbate (CH₃ O(a)_Ti4c ). CH₃ O(a)_Ti4c localized density of states are almost at the valence band maximum of TiO₂ surface, facilitating the interfacial hole transfer process; CH₃ O(a)_Ti4c with a high coverage promotes upward surface band bending, facilitating bulk-to-surface hole migration. CH₃ O(a)_Ti4c exhibits the highest photocatalytic oxidation rate constant. TiO₂ nanocrystals enclosed by the {001} facets are most active in photocatalytic methanol oxidation.

Keywords: electronic structure; methanol; nanocrystals; surface chemistry; surface photochemistry.

Grants and funding

21525313, 91745202, 91945301, 21825301, 21573211 and 21633007/National Natural Science Foundation of China