Oxidation of glycerol with H2O2 on Pb-promoted Pd/γ-Al2O3 catalysts

Abstract

A series of bimetallic Pd-Pb catalysts with a constant Pd content of 1 wt% and Pb/Pd atomic ratio from 0 to 1.6 supported on γ-Al<SUB>2</SUB>O<SUB>3</SUB> were prepared and used for glycerol oxidation with H<SUB>2</SUB>O<SUB>2</SUB> as the oxidizing agent at atmospheric pressure, 45℃ and pH=11. The morphology and dispersion of the catalysts were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) and transmission electron microscopy (TEM). The presence of an alloy phase in the bimetallic catalyst was detected by X-ray photoelectron spectroscopy (XPS). Glycerol conversion obtained with the monometallic Pd catalyst was 19%, which was increased to 100% with the addition of Pb. The four bimetallic PdPb catalysts were able to oxidize glycerol to dihydroxyacetone (DIHA) and the selectivity to DIHA reached 59%, 58%, 34% and 25% for PdPb0.25, PdPb0.50, PdPb1.00 and PdPb1.60 catalysts, respectively.