Can methanol be synthesized from CO by direct hydrogenation over Cu/ZnO catalysts?

Methanol synthesis from CO by direct hydrogenation has been studied using the density-functional theory (DFT). The charge of Cu has been found to be transferred to the ZnO carrier having low Cu cover. Due to the electron-charge transfer between the metallic Cu and the ZnO carrier, the Cu valency is greater than zero and less than one. Consideration of the water-gas-shift reaction and hydrogenation of CO2 to CHOO and COOH, the result shows that the active sites for the synthesis of methanol from CO2 and CO are different. Methanol is synthesized from CO by direct hydrogenation over Cuδ+ (0 < δ < 1) species through the intermediates CHO, CH2O, and CH3O, and the rate-limiting step is the hydrogenation of CHO, indicating that the Cuδ+ (0 < δ < 1) species comprise the active sites for the synthesis of methanol from CO by direct hydrogenation.