Promoting Role of Bismuth on Hydrotalcite-Supported Platinum Catalysts in Aqueous Phase Oxidation of Glycerol to Dihydroxyacetone

Bismuth plays important roles in promoting the oxidation of alcohols towards high-value-added chemicals over a noble metal loading catalyst. Herein, Mg-Al hydrotalcite-supported platinum-bismuth nanoparticles (Pt-Bi/HT) were prepared by the co-impregnation method and used in the selective oxidation of glycerol towards dihydroxyacetone (DHA). The incorporation of Bi species into Pt/HT significantly enhances the conversion of glycerol and the selectivity of DHA. The high selectivity of DHA with 80.6% could be achieved at 25.1% conversion of glycerol. The Bi species of the Pt-Bi/HT catalyst mainly exist in the form of BiOCl and Bi metal, which is different from the previous Pt-Bi based catalyst, confirmed by a combination of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). A plausible mechanism is proposed to elucidate the promoting role of Bi species on the Pt/HT catalyst in the selective oxidation of glycerol towards DHA.