Insight into the Effect of Cu Species and Its Origin in Pt-Based Catalysts on Reaction Pathways of Glycerol Oxidation

CuO-supported Pt–Cu nanoalloy catalysts were prepared to systematically explore the effect of metal introduction ways on the reaction path in the oxidation of glycerol, taking unsupported Pt–Cu catalysts and supported monometallic Pt catalysts as contrast. PtCu/CuO nanoalloys showed the preferable catalytic activity and high selectivity of dihydroxyacetone (DHA), while unsupported Pt–Cu sol catalysts tended to generate glyceraldehyde (GLD) and glyceric acid (GLA). This change in product distribution was due to the oxidation of the primary hydroxyl group when glycerol adsorbed on the Pt0–Cu0 site in Pt–Cu sol catalysts. However, in supported Pt–Cu alloy catalysts, owing to the contribution of Cu species in the support, the secondary hydroxyl group of glycerol preferred to adsorb on the Pt0–CuII sites with lower transition state energy for oxidation, responsible for higher DHA selectivity. This work provides a fundamental understanding on the effect of Cu species and its origin in Pt-based catalysts on the reaction pathways for glycerol oxidation.