Size effect on the adsorption and dissociation of CO2 on Co nanoclusters

Abstract

Spin-polarized density functional theory calculations were carried out to study the adsorption and dissociation properties of CO2 on size-selected Co13, Co38 and Co55 nanoclusters. Based on genetic algorithm method, Co13, Co38 and Co55 nanoclusters were predicted as the most stable high-symmetry structures among these Con (n=2–58) nanoclusters from the Gupta potential. For the adsorption of CO2, CO and O on size-selected Co13, Co38 and Co55 nanoclusters, the lowest adsorption strength is found for all the different adsorbates on Co55 nanocluster. For the dissociation of CO2 on these size-selected Co nanoclusters, the largest Co55 nanocluster possesses the greatest catalytic activity for the dissociation of CO2, with the smallest reaction barrier of 0.38eV. Our results reveal a non-monotonous behavior of the catalytic activities of Co nanoclusters on size, which is of fundamental interest for the design of new Co catalysts for the conversion of CO2.