Reaction Mechanism of CO2 Hydrogenation to Methanol on Indium Oxide Catalyst With Different Surface Structures
In2O3 is a promising catalyst for CO2 hydrogenation to methanol,but the mechanism for the deactivation of In2O3 and the structure-activity relationship of methanol synthesis have not been fully elaborated.For this reason,different surfaces with distinct structures of the cubic phase In2O3 were constructed,and then the mechanism of oxygen vacancy formation on the perfect In2O3 surfaces was studied using the density functional theory(DFT).The micro process for deactivation of In2O3 catalyst from oxide form to metallic In clusters by H2 reduction was stimulated.The In2O3(111)Step surface with relatively good resistance to sintering was selected for subsequent study on the mechanisms of CO2 adsorption and activation as well as methanol formation.The results show that as the number of oxygen vacancies on the In2O3 surface increases,the energy barrier for the reduction of In2O3 by H2 increases,and H2 dissociation becomes the rate-limiting step for oxygen vacancy formation.The defective In2O3(111)Step surface was demonstrated to have good activity and resistance to sintering.The reaction pathway involving HCOO*intermediate formation is the dominant path for methanol synthesis,in which the hydrogenation of bi-HCOO*intermediate species to bi-H2CO*and simultaneously fill the oxygen vacancies by deoxidation is determined as the rate-limiting step.
CO2 hydrogenationmethanol synthesisIn2O3 catalystdensity functional theoryreaction mechanismcatalyst deactivation mechanism
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