Nanoflower-like Cu/SiO2 Catalyst for Hydrogenation of Ethylene Carbonate to Methanol and Ethylene Glycol: Enriching H2 Adsorption

Graphical Cu-based catalyst : In the hydrogenation of ethylene carbonate (EC), nanoflower-like catalysts with high fiber density exhibited nearly 98 % EC conversion when the H 2 /EC ratio was decreased to 60, while the catalyst with solid sphere structure required at least a H 2 /EC ratio of 140. This is attributed to the H 2 -enrichment effect of nanoflower-like morphology with dense fibers, which accelerated the reaction rate and achieved excellent activity at a low H 2 /EC ratio. The hydrogenation of ethylene carbonate (EC) to produce methanol and ethylene glycol (EG) is one of the key steps in the promising route for CO 2 utilization on a large scale. However, the high H 2 /EC ratio in feed (usually as 200∼300) is generally required to achieve favorable catalytic activity, inducing the high cost for H 2 circulation in the industrial application. Here, we report a series of nanoflower-like catalysts with curved fibers and open ends, among which the catalyst with the highest fiber density exhibited nearly 98 % EC conversion, 75 % methanol selectivity and over 99 % EG selectivity when the H 2 /EC ratio was decreased to 60. Combining the characterizations of active species distribution and high-pressure H 2 adsorption, it is demonstrated that the nanoflower-like morphology with dense fibers could remarkably enrich the hydrogen adsorption, consequently, accelerate the reaction rate and present an excellent performance at a low H 2 /EC ratio. These insights may provide instructive suggestions for further design of catalysts for the hydrogenation reactions.