Design And Synthesis Of Pt(Pd)/PS/GNs Composites And Their Electro-photo-synergistic Catalytic Properties

In this paper, two-dimensional graphene nanosheets (GNs) were used as support materials to combine non-TiO2-based photosensitivity transition metal oxide (Cu2O and ZnO) or photosensitivity transition metal (Ag) with Pt (Pd) nanoparticles. The component structure and morphologies of the novel ternary nanocomposites were effectively controlled, in order to achieve stronger synergistic interaction between different components. And the synergistic effects between the electro-catalytic and photo-catalytic properties of as-synthesized composites drastically improve their catalytic performances for methanol oxidation reaction (MOR).Three different kinds of composites were prepared successfully by microwave reduction, hydrothermal reduction and impregnation-chemical reduction, respectively. The as-synthesized composites were listed as following:Pt (Pd)/Cu2O/GNs, Pt (Pd)/ZnO/GNs, Pt (Pd)-Ag/GNs. The components, constructions and morphologies of the composites were characterized by TEM, SEM, XRD, XPS, ICP and Raman spectra. Experimental data indicate that all the components had been successfully incorporated into the catalyst composites and the morphologies of Pt (Pd) nanoparticles were significately affected by the synthesis conditions and as-used photosensitivity species.Electrocatalytic properties of as-synthesized composites for MOR were evaluated by cyclic voltammetry (CV), chronoamperometry, COad stripping voltammetry and electrochemical impedance spectrum (EIS). The results showed that the as-synthesized composites exhibit remarkably improved electrocatalytic performances compared with the commercially available Johnson Matthey Pt/C catalyst (Pt/C-JM) and Sigma-aldrich Pd/C catalyst (Pd/C-SA). Especially under the light irradiation, the catalytic activity and stability of the as-synthesized composites drastically increases due to the existence of photosensitivity species, which stems from the synergistic effect between the electro-catalytic and photo-catalytic properties. It should be noted that the electro-photo synergistic catalysis of Pt (Pd)/ZnO/GNs and Pt (Pd)-Ag/GNs can been well realized under visible light irradiation, which is promising as a new anode electro-photo catalyst for DMFC. The results in this work provide a certain scientific theory and experimental basis for the design and practical application of novel anode DMFC catalysts.