乙醇在TiO2(110)表面光催化解离的动力学和超快电子动态学 (cited: 2)

采用实时双光子光电子能谱和时间分辨双光子光电子能谱技术分别研究了乙醇在该表面光催化解离的动力学和超快电子动态学过程. 通过测量与乙醇光催化解离相关的电子激发态随时间的演化，发现这个反应满足分型动力学. 乙醇在还原性TiO₂(110)上的光催化解离比在氧化性表面快，这归结于缺陷的存在降低了反应能垒. 这样一个反应的加速过程很可能是与缺陷电子相关的. 通过干涉双脉冲相关的测量，得到了乙醇-TiO₂界面电子激发态的超快动态学. 与甲醇的情况类似，这个电子激发态的寿命为24 fs. 激发态的出现为TiO₂和它周围环境的电子转移提供了一个通道.

Kinetics and Dynamics of Photocatalyzed Dissociation of Ethanol on TiO2(110) (cited: 2)

The kinetics and dynamics of photocatalyzed dissociation of ethanol on TiO₂(110) sur-face have been studied using the time-dependent and time-resolved femtosecond two-photon photoemission spectroscopy respectively, in order to unravel the photochemical properties of ethanol on this prototypical metal oxide surface. By monitoring the time evolution of the photoinduced excited state which is associated with the photocatalyzed dissociation of ethanol on Ti_5c sites of TiO₂(110), the fractal-like kinetics of this surface photocatalytic reaction has been obtained. The measured photocatalytic dissociation rate on reduced TiO₂(110) is faster than that on the oxidized surface. This is attributed to the larger defect density on the reduced surface which lowers the reaction barrier of the photocatalytic reaction at least methodologically. Possible reasons associated with the defect electrons for the acceleration have been discussed. By performing the interferometric two-pulse corre-lation on ethanol/TiO₂(110) interface, the ultrafast electron dynamics of the excited state has been measured. The analyzed lifetime (24 fs) of the excited state is similar to that on methanol/TiO₂(110). The appearance of the excited state provides a channel to mediate the electron transfer between the TiO₂ substrate and its environment. Therefore studying its ultrafast electron dynamics may lead to the understanding of the microscopic mechanism of photocatalysis and photoelectrochemical energy conversion on TiO₂.