Au7团簇吸附O2和CO及其对CO的催化反应机理研究

Theoretical study of the adsorptions of O2 and COas well as the CO oxidation on Au7 cluster

本文采用密度泛函理论,研究了Au7团簇催化CO的氧化反应机理.研究发现,二维平面结构的Au7团簇更容易吸附CO和O2分子.Au7团簇吸附一个O2分子的吸附能为0.64 eV,但在吸附多个O2分子时,平均吸附能有了明显的下降,表明Au7团簇进行多吸附O2分子的可能性不大.Au7团簇吸附一个CO分子的吸附能为1.26 eV,且在吸附多个CO分子时,平均吸附能虽有减少,但减小的幅度不大,说明Au7团簇有可能吸附多个CO分子.此外,在Au7团簇催化CO的氧化反应过程中,整个反应克服的最高势垒仅为0.34 eV,说明Au7团簇有望成为良好的CO氧化催化剂.

CO oxidation on the Au7 cluster is investigated by systematic density functional theory calculations.It is found that CO and O2 tend to adsorb on the Au7 cluster with two-dimensional structure.The adsorption energy for the O2 molecule is 0.64 eV.However,when more than one oxygen molecule is adsorbed,the average adsorption energy is reduced,indicating the Au7 cluster is difficulty to bind a high number of oxygen molecules.The adsorption energy for the CO molecule is 1.26 eV,and this system shows a remarkable capacity to bind a high number of CO molecules by the average adsorption energy.Moreover,the reaction energy barrier of CO oxidation reaction on Au7 cluster is only 0.34 eV,suggesting that Au7 cluster may be the most promising catalyst for CO oxidation.