期刊
APPLIED CATALYSIS B-ENVIRONMENTAL
卷 220, 期 -, 页码 126-136出版社
ELSEVIER
DOI: 10.1016/j.apcatb.2017.08.046
关键词
TiO2; Defect distribution; Surface/bulk; {001} facets; Photocatalytic hydrogen evolution
资金
- National Key Research and Development Program of China [2016YFB0600901]
- National Natural Science Foundation of China [21476159, 21525626, U1463205]
- 973 program [2014CB932403]
- Natural Science Foundation of Tianjin [15JCZDJC37400]
- Program of Introducing Talents of Disciplines to China Universities [B06006]
This paper describes the effects of defect distribution on energy band structure and the subsequent photo catalytic activity over TiO2 with exposed {001} facets as the model catalyst. Our results show that only surface oxygen vacancies (V-o's) and Ti3+ centers in TiO2 can be induced by hydrogenation treatment, whereas the generation of bulk Vo's and Ti3+ species depends on the thermal treatment in nitrogen. Both the surface and bulk defects in TiO2 can promote the separation of electron-hole pairs, enhance the light absorption, and increase the donor density. The presence of surface and bulk defects in TiO2 can not change the valence band maximum, but determine the conduction band minimum. Surface defects in TiO2 induce a tail of conduction band located above the H+/H-2 redox potential, which benefits the photocatalytic performance. However, bulk defects in TiO2 generate a band tail below the H+/H-2 potential, which inhibits hydrogen production. Thus, the change of band gap structure by defects is the major factor to determine the photocatalytic activity of TiO2 for hydrogen evolution. It is a new insight into the rational design and controllable synthesis of defect-engineered materials for various catalytic processes.
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