甲烷在O／Ni（100）表面上的反应动力学研究

DYNAMICAL STUDY OF DISSOCIATIVE CHEMISORPTION OF METHANE ON Ni(100) WITH PREADSORBED OXYGEN

甲烷在Ｏ／Ｎｉ（１００）表面上的反应动力学研究俞华根，程极源（中国科学院成都有机化学研究所，成都６１００１５）关键词甲烷，活化解离，预吸附氧，Ｎｉ（１００）表面，分子动力学，势能面甲烷在金属催化剂表面活化解离是重要的催化反应，受到了高度重视．近年来，...

model LEPS potential has been used to describe the interaction of gas-phase methane molecule with Ni(100) surface precovered with oxygen atom,in which CH4 is approximately considered as a two-body system (CH3 and H).The potential energy surface predicts a barrier with height of 0.427 eV for the activated dissociation of CH4 on O/Ni(100)surface. Based on this potential,the quasi-classical trajectory calculaf nons have been obtailled for CH4 scattered by nickel surface covered with oxygen atom. The dynamical results show that both translational and vibration21 energies are favourable to the dissociative chemisorption of CH4 on nickel. The obtained threshold energies are 0.62 eV for the ground-state CH4 and 0.39 eV for the first excited, respectively.In addition,the initial sticking probabilities of CH4 on ()/Ni(100) surface indicate that the preadsorbed oxygen atom on nickel surface are not of benefit to the dissociative chemisorption of CH4, which is in good agreement with the XPS experimental results reported by Alstrup et al[4].