title: The nature of photocatalytic "water splitting" on silicon nanowires.
abstract: Silicon should be an ideal semiconductor material if it can be proven usable for photocatalytic water splitting, given its high natural abundance. Thus it is imperative to explore the possibility of water splitting by running photocatalysis on a silicon surface and to decode the mechanism behind it. It is reported that hydrogen gas can indeed be produced from Si nanowires when illuminated in water, but the reactions are not a real water-splitting process. Instead, the production of hydrogen gas on the Si nanowires occurs through the cleavage of Si-H bonds and the formation of Si-OH bonds, resulting in the low probability of generating oxygen. On the other hand, these two types of surface dangling bonds both extract photoexcited electrons, whose competition greatly impacts on carrier lifetime and reaction efficiency. Thus surface chemistry holds the key to achieving high efficiency in such a photocatalytic system.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, and School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026 (P. R. China) http://staff.ustc.edu.cn/∼yjxiong/
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.forename: Leilei
authors.initials: L
authors.lastname: Li
authors.forename: Yang
authors.initials: Y
authors.lastname: Gao
authors.forename: Chengming
authors.initials: C
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.forename: Yujie
authors.initials: Y
authors.lastname: Xiong
keywords: charge separation; photocatalysis; semiconductors; silicon; surface chemistry