Abstract

As one of the most important photocatalysts, TiO2 has triggered broad interest and intensive studies for decades. Observation of the interfacial reactions between water and TiO2 at microscopic scale can provide key insight into the mechanisms of photocatalytic processes. Currently, experimental methodologies for characterizing photocatalytic reactions of anatase TiO2 are mostly confined to water vapor or single molecule chemistry. Here, we investigate the photocatalytic reaction of anatase TiO2 nanoparticles in water using liquid environmental transmission electron microscopy. A self-hydrogenated shell is observed on the TiO2 surface before the generation of hydrogen bubbles. First-principles calculations suggest that this shell is formed through subsurface diffusion of photo-reduced water protons generated at the aqueous TiO2 interface, which promotes photocatalytic hydrogen evolution by reducing the activation barrier for H2 (H–H bond) formation. Experiments confirm that the self-hydrogenated shell contains reduced titanium ions, and its thickness can increase to several nanometers with increasing UV illuminance.

Details

Title
Self-hydrogenated shell promoting photocatalytic H2 evolution on anatase TiO2
Author
Lu, Yue 1 ; Wen-Jin, Yin 2 ; Kai-Lin, Peng 3 ; Wang, Kuan 1 ; Hu, Qi 2 ; Selloni, Annabella 4 ; Fu-Rong, Chen 5 ; Li-Min, Liu 6   VIAFID ORCID Logo  ; Man-Ling, Sui 1   VIAFID ORCID Logo 

 Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing, China 
 Beijing Computational Science Research Center, Beijing, China 
 Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan, China 
 Department of Chemistry, Princeton University, Princeton, New Jersey, United States 
 Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan, China; Department of Materials Science and Engineering, City University, Hong Kong, China 
 Beijing Computational Science Research Center, Beijing, China; School of Physics, Beihang University, Beijing, China 
Pages
1-9
Publication year
2018
Publication date
Jul 2018
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2070785652
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.