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

The hydrogenation of ethylene carbonate (EC) to produce methanol and ethylene glycol (EG) is one of the key steps in the promising route for CO2 utilization on a large scale. However, the high H-2/EC ratio in feed (usually as 200 similar to 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.