Density functional study of CO2 adsorption on Pu(100) surface

Abstract

The adsorption of CO2 on Pu（100） surface has been studied with periodic slab model by revised Perdew-Burke-Ernzerh approximation within the framework of density functional theory. The optimized results of adsorption energies and geometrical structures show that the H-C4O4-type adsorption is optimum adsorption mode with adsorption energy of 1.48 eV. The atomic population and density of states analysis indicate that the interaction between Pu atom and CO2 molecule results mainly from strong electron transfer and weak overlap-hybridization between molecular orbital 2πμ of CO2 molecule and Pu5f, Pu6d and Pu7s orbitals of surface Pu atom. The calculated activation barrier and adsorption energy CO2→CO+O dissociative reaction are 0.66 and 2.65 eV, respectively, which indicates the dissociative adsorption of CO2 on Pu（100） surface is favorable under the certain heat activation condition. The comparison of O2，H2，CO and CO2 adsorption on Pu（100） surface indicates the adsorption strength follows the ordering: O2，CO，CO2，H2 and O2，CO2，CO，H2 at lower and higher temperature, respectively.