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The Nature of Photocatalytic “Water Splitting” on Silicon Nanowires
Author(s) -
Liu Dong,
Li Leilei,
Gao Yang,
Wang Chengming,
Jiang Jun,
Xiong Yujie
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201411200
Subject(s) - photocatalysis , nanowire , water splitting , materials science , silicon nanowires , silicon , photocatalytic water splitting , nanotechnology , engineering physics , optoelectronics , environmental science , chemistry , physics , catalysis , biochemistry
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 SiH bonds and the formation of SiOH 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.