Au_(38)团簇上小分子H_2O和O_2共同吸附的第一性原理研究

First-principles study of H_2O and O_2 adsorption on Au_(38) cluster

利用密度泛函理论(DFT)计算的方法,对O_2,H_2O单独吸附和共吸附在Au_(38)团簇上的吸附性质进行了结构,能量和电子分析.计算结果表明,O_2倾向于吸附在edge位,H_2O则倾向于吸附在top位.Au(100)表面较之Au(111)表面更有利于O_2,H_2O的吸附,这与实验结果相符合.H_2O和O_2共吸附研究表明,H_2O的存在促进了O_2的吸附.Mulliken和分态密度(PDOS)分析得出:在共吸附中,H_2O将部分电子转移给了O_2,促进了O_2的活化与解离,并生成了类似H_2O_2的中间态,从而为催化氧化反应提供了O活性物种.

Au38- O2, Au38- H2O, and Au38- H2O--O2 systems have been investigated by Density Functional Theory （DFT）. The studies of geometry, energy and electronic behavior show that O2and H2O tend to adsorb on edge sites and top sites respectively. It is found that O2, H2O are more favorable on Au （100） than Au （111） surface, which is in agreement with experimental result. The results of H2O and O2 coadsorption on Au38 cluster indicate that the presence of H2O promotes the adsorption of O2. Mulliken population and Partial Densities of States （PDOS） show electrons transfer from H2O to O2 in coadsorption structures, which promotes the activation and dissociation of O2, then generates a hydrogen peroxide-like intermediate state that provides O active species.