Selective Oxidation of Glycerol to Dihydroxyacetone over Au/CuZr_1-O Catalysts in Base-Free Conditions

In this paper, a series of Cu-Zr mixed metal oxide-supported Au catalysts were prepared by deposition-precipitation and evaluated for selective oxidation of glycerol to dihydroxyacetone (DHA) in base-free conditions. The best catalytic performance was obtained with DHA selectivity of up to 95% and yield of 70% in 4 h, 50 °C and P_O = 0.2 MPa over the Au/Cu_0.95Zr_0.05 and Au/Cu_0.9Zr_0.1 catalysts. Combined with the characterization results of Brunauer-Emmett-Teller, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and CO₂ temperature programmed desorption, it was proposed that the content of Au⁰, the size of Au, and the basicity of the catalyst affected the glycerol conversion and DHA selectivity. After the catalyst was recycled four times, the glycerol conversion decreased by about 14% which might result from the carbon deposition or the byproduct adsorption and the agglomeration of Au particle.