SO_2在Ni(111)表面分解吸附的理论研究  

DFT Study on the Decomposing Adsorption of SO_2 on Ni(111) Surface

作　　者：李俊[1] 申伟[1] 何荣幸[1] 李明[1] 

机构地区：[1]西南大学化学化工学院,重庆400715

出　　处：《西南大学学报（自然科学版）》2011年第5期68-73,共6页Journal of Southwest University(Natural Science Edition)

基　　金：重庆市自然科学基金重点项目(CSTC-2004BA4024)

摘　　要：采用密度泛函理论(DFT)的广义梯度近似(GGA)方法对SO2及其分解片段的吸附结构和性质进行了理论研究.计算结果表明:在Ni(111)表面上SO2以S,O原子顶位平铺吸附最稳定;SO3以C3v轴倾斜表面吸附;SO自由基存在两种可能的吸附结构,一种是平铺吸附于Ni(111)面,另一种是以S端垂直吸附穴位,S原子在穴位为最优吸附位.对各吸附体系的态密度及电子转移分析表明,SOx吸附中均为衬底镍原子向硫的氧化物转移电子,改变了S—O键之间的电子分布,导致其键长变长,这有利于硫氧化物在镍表面的解离反应.S原子在Ni(111)表面的吸附中,Ni原子的s轨道向S原子转移电子,这与O的吸附机理有所不同.The geometries and properties of SO2 and its fragments adsorbed on Ni（111） surface were systematically investigated by means of generalized gradient approximation（GGA） of the density functional theory（DFT）.The result indicates that SO2 is parallel to Ni（111） surface,its atoms are on the top site of Ni atoms,and SO3 is adsorbed on Ni（111） surface with its C3v axis declining to the surface.The adsorption geometries of SO have two possible structures： one is SO parallel to the surface,and the other is SO perpendicular to the surface with S atom absorbed to Ni surface.S atom is apt to adsorb on the hollow site.Analysis of the partial density of states and charge transfer indicates that the electrons of Ni atoms are transferred to SOx,thus resulting in the variation of the electron distribution of S—O bond and its elongation,which is helpful to the decomposition of SOx.The s orbital of Ni atom donates electrons to S atom in the adsorption of S atom on Ni（111） surface,which is different from the adsorption of O atom on Ni（111） surface.

关 键 词：密度泛函理论 表面吸附 SO2分解 态密度 

分 类 号：O643.12[理学—物理化学]