Catalyzed-like water enhanced mechanism of CO2 conversion to methanol

Abstract

Converting carbon dioxide to fine chemicals such as methanol using electrolytic hydrogen could be an efficient way of renewable energy storage. The conversion of CO2 to methanol is a rather complicated multistep process which is usually performed catalytically in gas phase. However, the aqueous phase conversion of CO2 is also feasible in certain conditions. Thus, a catalyzed-like water enhanced mechanism of CO2hydrogenation to methanol has been designed and studied by using the highly accurate W1U composite method. The initial reactant mixture was CO2 + 6H + 8H2O + H3O+, where the hydrogen atoms are added one-by-one to mimic the catalytic effect of a metal surface. The presence of water and H3O+ further enhance the reaction by lowering the reaction barriers. By computing the thermodynamic properties of the reaction mechanism, it was found that the highest relative energy barrier in the most preferred pathway is 212.67 kJ/mol. By taking this into account, the energy efficiency of the pathway has been calculated and it was found to be equal to 92.5%.