Glycerol Electrooxidation on Phosphorus-Doped Pt-αNi(OH)2/C Catalysts

Abstract

This work investigates the electrooxidation of glycerol in an alkaline environment at non-doped and P-doped Pt-αNi(OH)2 nanoparticles supported on oxidized Vulcan XC-72R carbon. Pt-αNi(OH)2 and PtP-αNi(OH)2 particles with sizes in the range of 3–5 nm were obtained via a one-step chemical reduction approach. The physicochemical characteristics of the as-prepared catalysts were studied by inductively coupled plasma-optical emission spectrometry (ICP-OES), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and x-ray diffraction (XRD) techniques. It was determined that the incorporation of phosphorus lead to the formation of amorphous PtP-αNi(OH)2 deposits. TEM analysis showed that the incorporation of phosphorus into the bimetallic Pt-αNi(OH)2 catalyst origins a remarkable reduction in the average size of the nanoparticles with a narrow size distribution. A substantial improvement in the electrocatalytic properties of the Pt-αNi(OH)2 system toward the oxidation of glycerol was observed through P doping. The P-doped electrocatalysts developed a mass current density of 60.3 mA mgPt−1 at 765 mV vs. RHE, which is about 5 and 45 times higher than those of commercial PtRu/C (12.3 mA mgPt−1) and as-synthesized Pt-αNi(OH)2/C (1.5 mA mgPt−1), respectively. The temperature-dependent experiments displayed that the apparent activation energy for the reaction is halved upon the addition of phosphorus.