Graphene And Polypyrrole Deposited Platinum Nanoparticles For The Performance Of Methanol Electrocatalysis

DMFC is an excellent power source because of its high energy density, lowpollution emission, low operating temperature, and ease of handing liquid fuel，whichcan be used as the power sources of many small electrical equipment. But the anodecatalyst of DMFC can be easily poisoned. In order to enhance the poisoning-toleranceand reduce the usage of Pt-based catalyst, it is necessary to seek for suitable supportsfor effective dispersion of catalyst particles. Nowdays, platinum nanomaterials werestill used widely for anode catalyst, which was decorated on the highly active carbonmaterials such as CNTs, graphene and conductive polymer. In this report, graphene（GNS）, PPy functionalied graphene （GNS-PPy） and polypyrrole nanospheres （PNS）were used as support materials for the PtNPs@GNS、 GNS-PPy/PtNPs, andPtNPs@PDDA-PNS catalysts. We examined the size of nanoparticles, surfacemorphology，crystal planes, catlytical activity and stability of catalyst.Graphene was prepared by arc discharge method, which can be used as thesupport materials for Pt-based catalyst because of high conductivity. Different massratios of platinum based catalysts were prepared by cyclic voltammetrys. The surfacemorphology, elements, crystal planes, surface chemical environment werecharacterized by SEM, EDS, XRD, XPS and Raman spectrum. In addition, thecatalytical activity and stability were measured by cyclic voltammetrys andamperometric i-t curve.The GNS was dropped on the surface of glassy carbon electrode. Then, thepolypyrrole-functionalized graphene （GNS-PPy） is constructed firstly with graphenenanosheets （GNS） and polypyrrole （PPy） particles by constant potential deposition.And then PtNPs are deposited on the surface of GNS-PPy by cyclic voltammetry（CV）. The surface morphology, elements, crystal planes, surface chemicalenvironment were characterized by SEM, EDS, XRD, XPS and Raman spectrum. Inaddition, the catalytical activity and stability were measured by cyclic voltammetrysand amperometric i-t curve. Polypyrrole nanospheres （PNS） with a diameter of60nm and high dispersionwere prepared by chemical polymerization of pyrrole. Then, PNS was functinalizedwith PDDA, which made the PNS possess large number of positively charged sites.These positive charges function as active sites attract negatively charged PtCl₆^2-ionsvia the electrostatic interactions. So the PtNPs@PDDA-PNS was obtained byreduction of the platinum precursor using NaBH4. The surface morphology, elements,crystal planes, surface chemical environment were characterized by SEM, EDS, XRD,XPS and Raman spectrum. In addition, the catalytical activity and stability weremeasured by cyclic voltammetrys and amperometric i-t curve, and compared withPtNPs@GNS, the result shows the catalytical activity is best when the platinumcontent is60%.