Preparation Of Pd/POMs/GN Composite Films And Their Electrocatalytic Performances For Formic Acid Oxidation

Direct formic acid fuel cell(DFAFC)gradually has attracted considerable attention due to its high quality energy density,small environmental pollution and easy to store and portable.Pd-based materials are the commonly used anodic electrocatalysts for formic acid oxidation.Recently,reducing the usage of Pd,improving the catalytic activity and the tolerance against CO have become main issues of researchers’consideration.Graphene is becoming a highly promising catalytic support material owing to its unique physical and chemical properties.It is expected that polyoxometalates(POMs)can effectively assist the electrochemical oxidation of carbon monoxide to carbon dioxide,which further prevents the catalyst form poisoning,owing to their superior redox properties.In this paper,functionalized graphene(PDDA-GN)is synthesized by reduction in the presence of hydrosoluble Poly(diallyldimethylammonium chloride)(PDDA).The{PDDA-GN/POMs(TMSPs)} support materials were fabricated by LBL method in order to electro-deposition Pd particles in situ.And three kinds of composite film catalysts,Pd/{PDDA-GN/POMs}n,PdCu/{PDDA-GN/PMo12}2 and Pd/{PDDA-GN/TMSPs}n were prepared.The particles size,composition and morphology of composite films were characterized by atomic force microscope(AFM),UV-vis and scanning electron microscope(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).The composites’ elements and their complex valence state are analyzed by X-ray photoelectron spectroscopy(XPS)and ICP-AES.It was found that all the components had been assembled into the resulting composite films with the small size distribution and high dipersion of Pd nanoparticles.Cyclic voltammetry(CV),chronoamperometry(I-t),CO stripping voltammetry and EIS were used to study the electrocatalytic activity of the as-prepared composite catalysts.The experiment data showed that the resulting composite catalysts present superior electrocatalytic activity,stability,CO tolerance ability and electron conductivity for formic acid oxidation.The {PDDA-GN/POMs(TMSPs)} composite films make metal particles to scatter more uniform,the intruoduction of POMs(TMSPs)enhances CO poisoning resistance.Addition of non-noble metal Cu also improves effectively the electrocatalytic activity of the as-prepared composites for formic acid oxidation.