Charge State Dependence of Phase Transition Catalysis of Dynamic Cu Clusters in CO2 Dissociation

The reactivity of subnanometer cluster catalysts depends on their charge state and dynamical evolutions of configurations under reaction environments. There have been some studies on how the dynamic configurational evolutions of neutral clusters influence their catalytic performances. However, there is little work on the charge state sensitivity of dynamic effects of metal clusters. In the present work, we investigate the dynamic process of CO2 dissociation on negatively and positively charged Cu-13 clusters and calculate the reaction free energy profiles using ab initio molecular dynamics. It is interesting to find that the reaction entropies are charge sensitive and show a different temperature dependence as compared to their neutral counterpart. In contrast to the single peaked shape shown in the neutral Cu-13 cluster, the entropy curves of the charged clusters exhibit an abnormal pulse shape. Further analysis indicates that such nontrivial entropy curves can be attributable to the adsorption-induced solid-to-liquid phase transitions of the charged clusters under finite temperature conditions. Our work reveals a complex temperature dependence of the chemical reaction on the charge state of the metal cluster.