TiO2(110)表面上甲醇吸附真实结构的多尺度密度泛函模拟

Methanol adsorption and dissociation on titania has received a wide attention because its potential application in photo-catalysis not only for the promotion of hydrogen production from water splitting but also its own ability of producing hydrogen by reforming. A number of studies were performed theoretically and experimentally so far, and valuable insights have been obtained in terms of adsorption sites and structures [Diebold, U. Surf. Sci. Rep. 2003, 48, 53; Pang, C. L.; Lindsay, R.; Thornton, G.; Chem. Soc. Rev. 2008, 37, 2328.] However, the structures of methanol adsorption from submonolayer to saturate coverage as well as its stability at different temperatures and pressures, which is prerequisite to develop meaningful model for relevant science, remains in controversial and misleading in literatures. To shed light on this, we present here a first-principles multi-scaling study of methanol adsorption and desorption on TiO2(110) surface by so-called ab initio thermodynamics and kinetic Monte Carlo (kMC) simulation. The thermodynamics analysis based on the density functional theory calculations shows that the methanol adsorption at coverage of 2/3 ML is prevailed at wide range of temperatures and pressures, and a full monolayer methanol structure presumed widely in literatures is however stable only at limited T/P windows. The temperature programmed desorption (TPD) spectroscopy are simulated using kMC, and the agreement with experiment [M. A. Henderson et al Faraday Discuss., 1999, 114, 313] is excellent. From the kMC simulation, a detailed microscopic kinetics of adsorption and desorption of methanol on TiO2(110) was mapped out for the first time. The implications of these findings will be discussed in this talk, and the importance of the multi-scaling study including T/P and kinetics will be highlighted