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

Spin-polarized density functional theory calculations were carried out to study the adsorption and dissociation properties of CO2 on size-selected Co-13,Co- Co-38 and Co-55 nanoclusters. Based on genetic algorithm method, Co-13, Co-38 and Co-55 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 Co-13, Co-38 and Co-55 nanoclusters, the lowest adsorption strength is found for all the different adsorbates on Co-55 nanocluster. For the dissociation of CO2 on these size-selected Co nanoclusters, the largest Co-55 nanocluster possesses the greatest catalytic activity for the dissociation of CO2, with the smallest reaction barrier of 0.38 eV. 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. (C) 2016 Elsevier B. V. All rights reserved.