A density-functional theory（DFT）method has been conducted to systematically investigate the adsorption of CHx（x=0～4）as well as the dissociation of CHx（x=1～4）on（111）facets of gold-alloyed Ni surface.The resul...A density-functional theory（DFT）method has been conducted to systematically investigate the adsorption of CHx（x=0～4）as well as the dissociation of CHx（x=1～4）on（111）facets of gold-alloyed Ni surface.The results have been compared with those obtained on pure Ni（111）surface.It shows that the adsorption energies of CHx（x=1～3）are lower,and the reaction barriers of CH4 dissociation are higher in the first and the fourth steps on gold-alloyed Ni（111）compared with those on pure Ni（111）.In particular,the rate-determining step for CH4 dissociation is considered as the first step of dehydrogenation on gold-alloyed Ni（111）,while it is the fourth step of dehydrogenation on pure Ni（111）.Furthermore,the activation barrier in rate-determining step is higher by 0.41 eV on gold-alloyed Ni（111）than that on pure Ni（111）.From above results,it can be concluded that carbon is not easy to form on gold-alloyed Ni（111）compared with that on pure Ni（111）.展开更多
基金supported financially by the National Basic Research Program of China(No.2005CB221203)the National Natural Science Foundation of China(No.20976115)the National Younger Natural Science Foundation of China(No.20906066)
文摘A density-functional theory（DFT）method has been conducted to systematically investigate the adsorption of CHx（x=0～4）as well as the dissociation of CHx（x=1～4）on（111）facets of gold-alloyed Ni surface.The results have been compared with those obtained on pure Ni（111）surface.It shows that the adsorption energies of CHx（x=1～3）are lower,and the reaction barriers of CH4 dissociation are higher in the first and the fourth steps on gold-alloyed Ni（111）compared with those on pure Ni（111）.In particular,the rate-determining step for CH4 dissociation is considered as the first step of dehydrogenation on gold-alloyed Ni（111）,while it is the fourth step of dehydrogenation on pure Ni（111）.Furthermore,the activation barrier in rate-determining step is higher by 0.41 eV on gold-alloyed Ni（111）than that on pure Ni（111）.From above results,it can be concluded that carbon is not easy to form on gold-alloyed Ni（111）compared with that on pure Ni（111）.
