Theoretical study of the geometries and decomposition energies of CO2 on Al12X: Doping effect of Al12X

The adsorption and decomposition of CO2 molecule on X-centered icosahedronal Al12X clusters (doping atom X = Al, Be, Zn, Fe, Ni, Cu, B, C, Si, P) were investigated by the DFT methods of PW91 and PWC. Adsorption energies, chemisorption energies and energy barriers of physic- and chemisorptions for CO2 were determined. It was found that the doping atoms and spin states have important influences on the Al12X geometries, electronic properties and energies of the adsorption processes. CO2 chemisorption on the Al12C cluster is energetically and kinetically unfavorable. CO2 decomposition on the metallic doping Al12X (X = Fe, Ni, Cu) clusters has relatively low energy barriers. On contrary, the barriers are large when X= B, C, Si and P. The energy barriers for CO2 chemisorption and decomposition on the Al12Fe cluster are 5.23 kJ/mol and 38.53 kJ/mol, respectively. These values are the lowest among all the clusters being discussed. The adsorption and decomposition of CO2 on the Al12X cluster can be tuned by X doping. (C) 2013 Elsevier Inc. All rights reserved.