Structures and electronic properties of Cu m Co n -CO 2 -H 2 O( m + n = 2~7) clusters

A theoretical study was carried out of CO2 and H2O co-adsorption on Cu m Co n (2 ≤ m + n ≤ 7) clusters using density functional method. The results show that, generally, CO2 molecules are adsorbed at top and bridge sites, but CO2 of Cu2CO4-CO2-H2O, Cu2Co5-CO2-H2O, and Co7-CO2-H2O clusters are at hollow sites. And H2O are all adsorbed at top sites via O atoms. Co5-CO2-H2O, CuCo2-CO2-H2O, Cu2Co-CO2-H2O, and Cu5Co-CO2-H2O clusters show better thermodynamic stability, while Cu2-CO2-H2O, Co2-CO2-H2O, Cu2Co-CO2-H2O, Cu3Co-CO2-H2O, and Cu6-CO2-H2O have stronger chemical stability. Mulliken charge and partial density of states are also analyzed for understanding the effect on interaction between CO2 and Cu-Co clusters after doping H2O.