The promotional effect of Ni on bimetallic PtNi/C catalysts for glycerol electrooxidation

The electrocatalytic oxidation of glycerol was studied using carbon-supported 20wt.% PtNi (PtNi/C) catalysts, which were prepared with different Pt:Ni atomic ratios from 3:1 to 1:1 using a colloidal method combined with a freeze-drying procedure. The bimetallic PtNi/C catalysts were characterized by various physicochemical analyses, including X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) measurements indicated that the addition of Ni with a Pt catalyst significantly improved the electrocatalytic activity for glycerol electrooxidation. Among the tested catalysts, the Pt2Ni1/C catalyst had approximately 61% higher mass activity than the Pt/C catalyst. Structural modification via lattice parameter change and electronic modification in the unfilled d band states for Pt atoms may kinetically facilitate the electrooxidation of glycerol with an increased exchange current density over the PtNi/C catalysts.