Fabrication Of Metal Nanoparticles Supported Composite Materials And Their Application As Electrochemical Catalysts

Direct methanol fuel cells(DMFCs) as their relatively widely available resources of the fuel and safety for the storage and transportations, high-energy conversion, low pollution emissions, system simplicity have received a great deal of attention recently. To explore new materials for DMFCs are helpful to solve the problem of the energy shortage and environmental pollution.Palladium nanoparticles(NPs) with uniformed size and high dispersion have been successfully assembled on the surface of reduced graphene oxide(RGO) via two different reduction processes. The loading amounts of Pd NPs on RGO is 10 wt%. The Pd/RGO was characterized with X-ray diffraction spectroscopy(XRD), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS), etc. Electrochemical studies revealed that the Pd/RGO nanocomposites prepared by NaBH4 reduction process exhibit the best electrochemical activity toward methanol and ethanol oxidation in alkali media than those using ascorbic acid as the reduction agent.A facile and green method for preparing Pt-Ag/RGO hybrids with different Pt/Ag ratios has been established. During the process, GO was used as reducing agent, and no additional reductants or surfactants were needed. The formation of Pt-Ag NPs was demonstrated by XRD, TEM and energy dispersive X-ray spectroscopy(EDS). Compared with Pt/RGO, the Pt-Ag/RGO has superior electrocatalytic activity for the oxidation of methanol and ethanol in acid media.Simultaneous redox reactions between K2PdCl4, HAuCl4, AgNO3, and graphene oxide(GO) are used to prepare Pd-Au-Ag NPs supported on RGO. The GO serves as the reducing agent, stabilizing agent and the support. The morphology and composition of the Pd-Au-Ag(1:1:1)/RGO NPs are characterized by TEM, XRD, XPS, etc. The prepared Pd-Au-Ag(1:1:1)/RGO has good electrocatalytic activity and stability for the oxidation of methanol and ethanol in alkaline media.