Carbon supported Pt₉Sn₁ nanoparticles as an efficient nanocatalyst for glycerol oxidation

Glycerol derived from biomass is increasingly attractive as a renewable feedstock for production of bulk and specialty chemicals. In this work, we have developed an efficient Pt₉Sn₁/C nanocatalyst for oxidation of glycerol to glyceric acid, with its activity the highest among various PtM/C (M=Mn, Fe, Co, Ni, Cu, Zn, Au) bimetallic nanocatalysts. Under the optimized conditions, 91% of glycerol can be oxidized within 8h at 60°C, with 50% yield of glyceric acid. Without incorporation of Sn, a lower glycerol conversion of around 69% was obtained over the monometallic 2.0%Pt/C-R catalyst under the same reaction conditions. Furthermore, the calculated turn over frequency (TOF) based on surface Pt atoms is 938h^-1 for 2.0%Pt₉Sn₁/C-R nanocatalyst, which is three times as high as that of 2.0%Pt/C-R catalyst (281h^-1). The enhancement of activity by modifying Pt nanoparticles with Sn is attributed to activation of oxygen molecules and/or deprotonation of hydroxyl group by surface stannous oxide (SnO) species. In addition, the Pt₉Sn₁/C-R catalyst has been shown to be robust and stable without substantial loss of activity after being recycled for four times.