title: Effects of Zn2+ and Pb2+ dopants on the activity of Ga2O3-based photocatalysts for water splitting.
abstract: Zn-doped and Pb-doped β-Ga2O3-based photocatalysts were prepared by an impregnation method. The photocatalyst based on the Zn-doped β-Ga2O3 shows a greatly enhanced activity in water splitting while the Pb-doped β-Ga2O3 one shows a dramatic decrease in activity. The effects of Zn(2+) and Pb(2+) dopants on the activity of Ga2O3-based photocatalysts for water splitting were investigated by HRTEM, XPS and time-resolved IR spectroscopy. A ZnGa2O4-β-Ga2O3 heterojunction is formed in the surface region of the Zn-doped β-Ga2O3 and a slower decay of photogenerated electrons is observed. The ZnGa2O4-β-Ga2O3 heterojunction exhibits type-II band alignment and facilitates charge separation, thus leading to an enhanced photocatalytic activity for water splitting. Unlike Zn(2+) ions, Pb(2+) ions are coordinated by oxygen atoms to form polyhedra as dopants, resulting in distorted surface structure and fast decay of photogenerated electrons of β-Ga2O3. These results suggest that the Pb dopants act as charge recombination centers expediting the recombination of photogenerated electrons and holes, thus decreasing the photocatalytic activity.
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China. canli@dicp.ac.cn.
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.forename: Shuai
authors.initials: S
authors.lastname: Shen
authors.forename: Shaoqing
authors.initials: S
authors.lastname: Jin
authors.forename: Jingxiu
authors.initials: J
authors.lastname: Yang
authors.forename: Mingrun
authors.initials: M
authors.lastname: Li
authors.forename: Xiuli
authors.initials: X
authors.lastname: Wang
authors.forename: Hongxian
authors.initials: H
authors.lastname: Han
authors.forename: Can
authors.initials: C
authors.lastname: Li