金属催化剂对CO气敏薄膜特性影响的密度泛函法分析

Influence of Metal Catalyst on Characteristics of CO Gas Sensitive Thin Film Based on Density Functional Analysis

根据密度泛函理论,采用总体能量平面波赝势方法,计算了CO气体敏感薄膜中几种常用金属催化剂(P T,PD,CU,A G)的能量最低晶面,并对CO在这些晶面上的吸附特性进行了研究.从结合能、C O键长、轨道布居、态密度等方面比较了C与金属成键强度及CO分子被活化程度.计算结果发现,CO在金属表面的吸附强度及金属对CO催化效果强弱的顺序是:P T>PD>CU>A G.得出结论:对于CO气体传感器,P T是通过金属催化剂添加提高灵敏度的最佳选择.

Based on density functional theory and the total energy plane-wave pseudopotential, the lowest-energy surfaces of several typical metal catalysts （Pt, Pd, Cu, and Ag） for CO gas sensitive thin-film are calculated, and their CO adsorption characteristics are analyzed. The chemisorption properties, including the length of C--O bond, orbital population and density of states, are computed and analyzed respectively. The results indicate that both the intensity of C-Metal bonds and the catalytic effect of the metals on CO are in the same sequence of Pt〉Pd〉Cu〉Ag. In conclusion, Pt is the best choice for CO thin-film gas sensors as catalyst.