Density Functional Theory Study for Catalytic Activation and Dissociation of CO2 on Bimetallic Alloy Surfaces

Abstract

CO2 has a potentially bright future as a carbon resource because it is very cheap and abundant. The conversion technology of CO2 into useful chemicals therefore has gained growing attention over recent years. Despite many attempts, there have not yet been revolutionary successes for commercialization of such technology. One of the main challenges in this field is to catalytically activate the CO2 molecule on the surfaces of catalysts. Although many researchers have studied the catalytic reactions involving CO2 on the surfaces, the activation process of CO2 is still controversial. Here, we performed density functional theory calculations to understand the CO2 activation and dissociation on a wide range of bimetallic alloy surfaces. To begin with, the adsorption process of CO2 on pure metal surfaces was carefully examined with the analyses of adsorption energetics, geometries, vibrational frequencies, charge transfers, and density of states. From the activated CO2 on the surfaces, we could precisely capture the transition state of the dissociation reaction. On the basis of the information, we found that Bronsted-Evans-Polanyi (BEP) relations hold for CO2 dissociation reaction. It was also verified that the sum of adsorption energies of CO and O is linearly scaled with not only adsorption energy of CO2 delta- but also reaction energy for the CO2 dissociation. As a result, the energy barriers of CO2 dissociation on pure metal and bimetallic alloy surfaces could be rapidly screened by combining the BEP relation, scaling relation, and surface mixing rule. Our results will provide useful insight into designing transition metal catalysts for the CO2-involved reactions.