CO2 hydrogenation to methanol over the copper promoted In2O3 catalyst

The metal promoted In2O3catalysts for CO2hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity.However,there was still no experimental confirmation if copper could be a good promoter for In2O3.Herein,the Cu promoted In2O3catalyst was prepared using a deposition-precipitation method.Such prepared Cu/In2O3catalyst shows significantly higher CO2conversion and space time yield(STY) of methanol,compared to the un-promoted In2O3catalyst.The loading of Cu facilitates the activation of both H2and CO2with the interface between the Cu cluster and defective In2O3as the active site.The Cu/In2O3catalyst takes the CO hydrogenation pathway for methanol synthesis from CO2hydrogenation.It exhibits a unique size effect on the CO adsorption.At temperatures below 250℃,CO adsorption on Cu/In2O3is stronger than that on In2O3,causing higher methanol selectivity.With increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity.Compared with other metal promoted In2O3catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.