Yongchun Zhao,* Zhuo Xiong, Ze Lei, Junying Zhang, Chuguang Zheng
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, 1037 Luoyu Road, Wuhan 430074, China
Nano-Micro Conference, 2017, 1, 01053
Published Online: 28 October 2017 (Abstract)
Corresponding Author. Email: yczhao @hust.edu.cn


CO2 photocatalytic reduction with water is one of the most popular and challenging technologies to produce renewable energy. Engineering TiO2 with coexposed {001} and {101} facets could enhance the conversion efficiency of CO2 due to the effective separation of photogenerated charges caused by the formation of {001}/{101} surface heterojunction. However, faceted TiO2 nanocrystals still suffers from low conversion effiency and low selectivity for CO2 reduction. Faceted TiO2 nanocrystals were combined with graphene and metal nanoparticles respectively to improve the activity and selectivity of CO2 photocatalytic reduction. The results show that the faceted TiO2/graphene composites exhibited higher CO yield than that of pristine TiO2 due to the formation of {001}/{101} surface heterojunction and supporting of graphene, which can effectively promote the spatial separation of photogenerated electrons and holes. Differing from graphene, Pt loading tended to promote the production of CH4 and H2 while Cu2O suppressed H2 evolution and exhibited lower CH4 selectivity comparing with Pt. Furthermore, when Pt and Cu2O were co-deposited on TiO2 crystals, H2 and CO production were both inhibited and CO2 was selectively reduced to CH4. Pt could not only capture photogenerated electrons but also increase the electrons density on the surface of TiO2. Meanwhile, Cu2O loading enhanced the CO2 chemisorption on TiO2 while inhibited that of water. As a result, Pt and Cu2O co-deposited TiO2 crystals exhibited high selectivity for CH4 production.


Figure 1. Schematic diagram of graphene and metal modified faceted TiO2 nanocrystals.


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