水分子在不同二氧化钛表面的光催化解离机理研究

项目名称： 水分子在不同二氧化钛表面的光催化解离机理研究

项目编号： No.21503223

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 徐晨彪

作者单位： 中国科学院大连化学物理研究所

项目金额： 21万元

中文摘要： 氢能源是面向未来应用的理想洁净能源。二氧化钛(TiO2)具有优良的光催化性能，在光催化分解水产氢方面有着巨大的潜在应用前景。目前的研究工作主要集中在催化材料改性以提高光催化效率方面，而光催化反应机理问题仍不是十分清楚。本项目拟利用超低背景程序升温脱附谱和高灵敏度飞行时间质谱相结合的探测手段，结合紫外波段连续可调的皮秒激光光源，探索水分子在rutile-TiO2 (110)和anatase-TiO2 (101)单晶表面的光催化解离动力学机制和产氢机理。初步实验结果表明，应用400nm激光光照观测不到水分子在rutile (110)表面的解离行为，而266nm激光光照时探测到光致解离产物-OH自由基。本项目拟在此基础上系统研究不同吸附量条件，表面氢键作用及不同激发波长对水分子光催化解离动力学过程的影响，真正在分子水平上理解光化学反应过程的微观机理，为设计发展新型高效催化剂提供理论支持。

中文关键词： 二氧化钛；表面动力学；表面光催化；程序升温脱附谱；飞行时间质谱

英文摘要： Hydrogen is considered to be an ideal clean energy carrier in the foreseeable future. Titanium dioxide (TiO2) is a candidate catalyst for producing hydrogen due to its interesting photocatalytic properties. Even though lots of studies have been focused on TiO2 materials for hydrogen production via photocatalytic water splitting, the photocatalytic reaction mechanism of water splitting remains unclear. In this proposal, we plan to study the fundamental mechanism of water splitting and hydrogen production on the rutile-TiO2(110) and anatase-TiO2(101) single crystal surfaces, using ultra-low background temperature programmed desorption (TPD) spectroscopy and high sensitive time of flight (TOF) spectroscopy combined with tunable picosecond light source. The preliminary experimental results show no dissociation of water molecules on rutile-TiO2(110) under 400 nm laser irradiation was observed, but the OH radical product from water dissociation has been detected with 266nm laser irradiation. In this project, we intend to systematically investigate the microscopic mechanism of photocatalytic water splitting and hydrogen production by careful study of the dynamics of bond breaking and forming, surface electron-hole pair excitation, and energy transfer using TPD and TOF methods, and then provide some clues for improving the efficiency of TiO2 catalysts on hydrogen production and give a more deep insight in understanding the nature of photocatalytic reactions on TiO2.

英文关键词： Titanium Dioxide;Surface Dynamics;Photocatalysis;Temperature Programmed Desorption Spectroscopy;Time of Flight Spectroscopy