Surface Engineering of TiO<sub>2</sub> Nanosheets to Boost Photocatalytic Methanol Dehydrogenation for Hydrogen Evolution
Fengyang Yu, Xiaohua Wang, Haiyue Lu, Gen Li, Baicheng Liao, Hanqing Wang, Chunying Duan, Yu Mao, Liyong Chen
Abstract
Low-cost high-efficiency H 2 evolution is indispensable for its large-scale applications in the future. In the research, we expect to build high active photocatalysts for sunlight-driven H 2 production by surface engineering to adjust the work function of photocatalyst surfaces, adsorption/desorption ability of substrates and products, and reaction activation energy barrier. Single-atom Pt-doped TiO 2– x nanosheets (NSs), mainly including two facets of (001) and (101), with loading of Pt nanoparticles (NPs) at their edges (Pt/TiO 2– x -SAP) are successfully prepared by an oxygen vacancy-engaged synthetic strategy. According to the theoretical simulation, the implanted single-atom Pt can change the surface work function of TiO 2, which benefits electron transfer, and electrons tend to gather at Pt NPs adsorbed at (101) facet-related edges of TiO 2 NSs for H 2 evolution. Pt/TiO 2– x -SAP exhibits ultrahigh photocatalytic performance of hydrogen evolution from dry methanol with a quantum yield of 90.8% that is ∼1385 times higher than pure TiO 2– x NSs upon 365 nm light irradiation. The high H 2 generation rate (607 mmol g cata –1 h –1 ) of Pt/TiO 2– x -SAP is the basis for its potential applications in the transportation field with irradiation of UV–visible light (100 mW cm –2 ). Finally, lower adsorption energy for HCHO on Ti sites originated from TiO 2 (001) doping single-atom Pt is responsible for high selective dehydrogenation of methanol to HCHO, and H tends to favorably gather at Pt NPs on the TiO 2 (101) surface to produce H 2 .