Hydrogenolysis of Bio-Glycerol over In Situ Generated Nanosized Cu-ZnO Catalysts

Abstract

Due to the growth of biodiesel production, utilization of the glycerol formed as a by-product is still of considerable importance. This study is devoted to a novel approach for glycerol hydrogenolysis with use of in situ generated Cu-ZnO catalysts. The main product formed is 1,2-propanediol, with the by-products being lactic acid and ethylene glycol. The Cu-ZnO catalysts are characterized by AAS, XRD, XPS, SEM, TEM, EDX, BET, and chemisorption N2O. The proportion of ZnO turns out to have a significant effect on the activity and selectivity of the catalyst formed. Increasing the ZnO content enables one to obtain more dispersed, active, selective, and agglomeration-resistant catalysts. The transition from monometallic Cu catalysts to Cu-ZnO with a ZnO content of 65 wt% allows one to increase selectivity from 74 to 86%, TOF from 0.136 to 0.511 s−1, and SCu from 1.9 to 7.1 m2/g-Cu. The morphology of the synthesized Cu-ZnO catalysts resembles the structure of oxide/metal inverse catalysts.