Facile Synthesis of Cu@CeO2 and Its Catalytic Behavior for the Hydrogenation of Methyl Acetate to Ethanol

The hydrogenation of methyl acetate (MA) is one of the key steps in the synthesis of ethanol from syngas. Given previous studies in this area, synergy of the Cu-0 and Cu+ species is the crux to improving catalytic performance. However, neither Cu-0 nor Cu+ is easy to maintain under reaction conditions comprising abundant H-2 and high temperature. Here, a Cu@CeO2 core-shell catalyst was fabricated by using a facile sol-gel method, and this catalyst exhibited excellent activity and stability in the hydrogenation of MA. It was revealed that the Cu@CeO2 core-shell structure prevented the metallic copper particles from migrating and aggregating and also significantly increased the amount of Cu+ species by enlarging the intimate contact area of copper and ceria. Furthermore, the Cu-0 and Cu+ species were found to be well distributed on the interface between the Cu core and the CeO2 shell. The close relative position of the two active sites is probably the main reason for the enhanced synergetic effect in the hydrogenation of MA. New insight into the core-shell structure-function relationship introduces new possibilities for the rational design of catalysts.