Rh(111)表面上CO和O共吸附的密度泛函理论计算研究

A Density Functional Theory Study on Co-adsorption of CO and O on Rh(111) Surface

采用密度泛函理论对Rh(111)表面上CO和O的吸附和共吸附进行了系统的研究,计算了三类不同的共吸附结构.从吸附能和化学位移的角度,通过与已有实验结果对比,推断出可能存在的吸附构型.CO和O之间存在较大的排斥作用,在表面上竞争吸附.电子结构分析发现,这种排斥作用来源于CO和O之间与Rh的d轨道成键的竞争.用密度泛函理论计算的化学位移与实验测量结果一致,说明化学位移的理论计算能辅助对表面结构的预测.

CO and O adsorption and co-adsorption on Rh（ 111 ） surfaces were studied by density functional theory calculations, Three types of co-adsorption systems, （2 × 2）-（CO＋ O）, （2 × 2）-（2CO＋ O）, and （2 × 2）-（CO＋ 2O）, were considered from energy, geometry, work function, and chemical shift points of view. The interactions between CO and O are repulsive, which is explained in terms of bonding competition. The calculated chemical shift of CO and O agrees well with experimental studies, which convince that it is a powerful method to predict the adsorption from theoretical chemical shifts.