杂质对担载式催化剂化学吸附的影响

IMPURITY EFFECTS ON CHEMISORPTION OF COMPOSITE CATALYSTS

本文采用化学吸附的格林函数理论和复能量积分方法研究H在担载式催化剂ZnO/Ni上的化学吸附,使用由s轨道和p轨道交迭排列的有限原子链和由d轨道组成的半无限原子链,以描述半导体ZnO和金属Ni构成的复合衬底,用Koster-Slater模型来表示杂质原子,分别研究了化学吸附能随ZnO层厚度的变化和化学吸附能与掺杂的关系,结果表明:1)H的化学吸附能随ZnO层数的增加而单调地减小;2)在Ni中掺入杂质Cu和Pt会削弱H的化学吸附,而掺入Co和W将加强H的吸附;3)Ni中的杂质位于界面附近时对化学吸附能的影响最大。

The chemisorption energy of hydrogen on ZnO/Ni composite substrate is investigated using the Green function method and the complex-energy-plane integration approach. The tight-binding approximation is employed to model the semiconductor ZnO by a finite chain of alternating s- and p-orbitals, while the semi-infinite metal Ni is represented by a linear chain of d-orbitals. The impurity effect on the chemisorption energy is evaluated. The calculation shows that: (1) the chemisorption energy is a monotonously decreasing function of the ZnO thickness; (2) the presence of impurities Cu and Pt (Co and W) can weaken (strengthen) the chemisorption process and (3) the impurity effects are most significant when the impurity is closest to the nickel surface.