Fabrication of a composite of platinum, N-g-C.sub.3N.sub.4 and Ketjen Black for photo-electrochemical methanol oxidation

Recently N-doped graphitic carbon-incorporated g-C.sub.3N.sub.4 (denoted as N-g-C.sub.3N.sub.4) exhibits better electroconductivity and photo-catalytic property compared with pure g-C.sub.3N.sub.4 as a support material for Pt nanoparticles (NPs). A composite catalyst consisting of Pt nanoparticles and N-g-C.sub.3N.sub.4-modified KB was designed and fabricated. Pt nanoparticles were prepared through a solution plasma process; N-g-C.sub.3N.sub.4 was prepared by direct heating the mixture of urea and citric acid monohydrate and subsequently treated by hydrothermal method. Their chemical composition, particle size and microstructure were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. Compared with the Pt/KB catalyst, ternary Pt/N-g-C.sub.3N.sub.4/KB nanocomposites exhibit excellent electrocatalytic properties for methanol oxidation owning to the significant synergistic effects of individual components. Once light irradiation was supplied, Pt/N-g-C.sub.3N.sub.4/KB catalyst exhibits exceptional forward peak current densities as high as 2800 mA mgPt-1. And Pt/N-g-C.sub.3N.sub.4/KB catalyst also shows better CO tolerance than Pt/KB. Such a Pt/N-g-C.sub.3N.sub.4/KB composite catalyst may bring new design ideas for photo-assisted direct methanol fuel cell in the future.