Onda Ken, Li Bin, Zhao Jin, Jordan Kenneth D, Yang Jinlong, Petek Hrvoje
Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Science. 2005 May 20;308(5725):1154-8. doi: 10.1126/science.1109366.
At interfaces of metal oxide and water, partially hydrated or "wet-electron" states represent the lowest energy pathway for electron transfer. We studied the photoinduced electron transfer at the H2O/TiO2(110) interface by means of time-resolved two-photon photoemission spectroscopy and electronic structure theory. At approximately 1-monolayer coverage of water on partially hydroxylated TiO2 surfaces, we found an unoccupied electronic state 2.4 electron volts above the Fermi level. Density functional theory shows this to be a wet-electron state analogous to that reported in water clusters and which is distinct from hydrated electrons observed on water-covered metal surfaces. The decay of electrons from the wet-electron state to the conduction band of TiO2 occurs in </=15 femtoseconds.
在金属氧化物与水的界面处，部分水合或“湿电子”状态代表了电子转移的最低能量路径。我们通过时间分辨双光子光电子能谱和电子结构理论研究了H₂O/TiO₂(110)界面处的光致电子转移。在部分羟基化的TiO₂表面上，当水的覆盖量约为1个单层时，我们发现了一个比费米能级高2.4电子伏特的未占据电子态。密度泛函理论表明，这是一种类似于在水簇中报道的湿电子态，与在水覆盖的金属表面上观察到的水合电子不同。从湿电子态到TiO₂导带的电子衰减发生在≤15飞秒内。
