铂催化甲醇氧化开始步骤的研究

Study of the Initial Steps of Methanol Electrooxidation Catalyzed by Pt

用abinitio和密度泛函(DFT)方法研究甲醇在铂低指数晶面的脱氢步骤.在经典的Bagotzky模型计算的基础上提出了三种新的吸附脱氢模型,并通过计算证明了三种模型的可行性,计算证实了原位波谱法检测到的甲醇在铂上脱氢的三种中间体,CHOH,CH2OH和CH3O.得出了甲醇脱氢的根本原因在于形成的强Pt—H键,且在Pt不同的晶面上,催化性能及反应历程、中间产物都不同.

The dehydrogenation of methanol on low-index single Pt crystal surfaces has been studied by means of the ab initio and DFT approaches. Besides the well-known Bagotzky pattern, three adsorptive and dehydrogenation patterns of methanol on platinum were put forward and confirmed through the ab initio calculations. The three in situ detected intermediates of methanol dehydrogenation on Pt surface, i.e., CHOH, CH2OH and CH30, were confirmed by ab initio and DFT approaches. It is concluded that whether hydrogen atom dehydrogenates from methanol molecule depends on whether it is absorbed by Pt atom and forms Pt--H bond. Different adsorptive patterns occured on different platinum planes correspondingly because of the specific atomic arrangement and electronic structure of Pt planes, leading to specific intermediates on platinum surface.