氢在镍晶面上的吸附态研究

应用EHMO法研究镍上吸附氢的各种可能吸附态.结果表明,晶面上吸附氢原子(H~*)的势能变化均呈Morse函数形式,而由结合能计算值确定的相对有利吸附位,优先吸附面以及吸附热和扩散活化能等方面大体均能说明多数实验事实.

Study of Adsorption States of Hydrogen on Nickel Surface

A series of possible states of hydrogen adsorption on nickel surface has been studied by EHMO method.The results show that the potential curves of hydrogen adatom take the form of Morse's function. The relatively favorable positions to be occupied by H adatom are the 'on top' or 'on bridge'sites for three close packed Ni planes. While the (110)and(111) are the planes for predominant adsorption. Derived from 'binding energy' according to Eley-Stevenson equation, the adsorption heat is about 80-100kJ.mol-1(H). However, the H adatoms seem to be unlocalized on nickel surface, and may be diffuse along the lattice plane, ths activation energy for diffusion ranging between 8 to 17kJ.mol-1.The conclusions coincide with several experimental facts ing eneral.