Yang Wenshao, Wei Dong, Jin Xianchi, Xu Chenbiao, Geng Zhenhua, Guo Qing, Ma Zhibo, Dai Dongxu, Fan Hongjun, Yang Xueming
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics , 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China.
J Phys Chem Lett. 2016 Feb 18;7(4):603-8. doi: 10.1021/acs.jpclett.6b00015. Epub 2016 Jan 27.
Photoinduced water dissociation on rutile-TiO2 was investigated using various methods. Experimental results reveal that the water dissociation occurs via transferring an H atom to a bridge bonded oxygen site and ejecting an OH radical to the gas phase during irradiation. The reaction is strongly suppressed as the water coverage increases. Further scanning tunneling microscopy study demonstrates that hydrogen bonds between water molecules have a dramatic effect on the reaction. Interestingly, a single hydrogen bond in water dimer enhances the water dissociation reaction, while one-dimensional hydrogen bonds in water chains inhibit the reaction. Density functional theory calculations indicate that the effect of hydrogen bonds on the OH dissociation energy is likely the origin of this remarkable behavior. The results suggest that avoiding a strong hydrogen bond network between water molecules is crucial for water splitting.
利用多种方法研究了金红石型二氧化钛上的光致水分解。实验结果表明，在光照过程中，水分解是通过将一个氢原子转移到桥连键合的氧位点，并向气相中喷射出一个羟基自由基来实现的。随着水覆盖率的增加，该反应受到强烈抑制。进一步的扫描隧道显微镜研究表明，水分子之间的氢键对该反应有显著影响。有趣的是，水二聚体中的单个氢键增强了水分解反应，而水链中的一维氢键则抑制了该反应。密度泛函理论计算表明，氢键对羟基解离能的影响可能是这种显著行为的起源。结果表明，避免水分子之间形成强氢键网络对于水分解至关重要。
