PdMn and PdFe nanoparticles over a reduced graphene oxide carrier for methanol electro-oxidation under alkaline conditions

Abstract

PdMn and PdFe nanoparticles supported reduced graphene oxide catalysts (RGO) are synthesized by sodium borohydride reduction using polyethylene glycol (PEG) as a protective agent. The prepared catalysts are used to electro-catalyse methanol under alkaline conditions. These catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The test results show that the dispersibility and size of the catalysts are modulated by the addition of the second metal. Cyclic voltammetry (CV) and chronoamperometry tests show that, compared with the Pd/RGO catalyst, the electrochemical activities of the PdMn/RGO and PdFe/RGO catalysts are enhanced, and their electrochemical stabilities are improved for methanol oxidation. Electrochemical tests show that PdMn/RGO and PdFe/RGO have lower initial potential for methanol oxidation than Pd/RGO, which indicates that the prepared Pd-based bimetallic catalysts have better electrochemical performance than Pd/RGO catalyst. Further, the electronic structure of Pd is also successfully changed, which has a significant impact on improving the stability and electrochemical activity for methanol oxidation. In summation, PdMn/RGO and PdFe/RGO catalysts show better electrochemical performance for methanol oxidation than the Pd/RGO catalyst.