Direct production of ethanol with high yield from glycerol via synergistic catalysis by Pd/CoOx and Cu/SBA-15

Direct hydrogenolysis of glycerol to ethanol in liquid phase was studied for the first time in this work, and the results showed that Pd/CoOx gave high ethanol selectivity and good reusability. The reaction pathways were thoroughly investigated, and it was found that ethanol was mainly produced by consecutive hydrogenolysis of glycerol with 1,2-propanediol as intermediate. More importantly, PdCo alloy was identified as the main active site for ethanol production from glycerol by in situ XRD, TEM, H2-TPR, XPS and controlled experiments. Remarkably, Cu/SBA-15 was employed as co-catalyst to adjust the reaction routes and inhibit Pd/CoOx aggregation. By synergistic catalysis of Pd/CoOx and Cu/SBA-15, the yield of ethanol then reached to 84.5%, which is the highest value ever reported in glycerol hydrogenolysis reactions.