The Preparation Of Carbon Nanotubes Loaded Platinum-Heteropoly Acid Nanocomposite And Study Of Its Electrocatalytic Properties

Carbon nanotubes (CNTs) were grafted with poly(4-vinylpyridine)(PV4P) in aqueous solution by in situ free radical polymerization of4-vinylpyridine (PV4P-g-CNT). PV4P-g-CNTs can load a polyoxometalate, such as phosphotungstic acid (PW). PW/PV4P-g-CNTs were prepared by electrostatic interaction and their composition was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Scanning and Transmission electron microscopy show that PW is deposited on PV4P-g-CNTs, and forms a uniform layer. The as-prepared PW/PV4P-g-CNTs were modified onto a carbon glassy electrode. Cyclic voltammetry shows that the electrochemical behavior of the modified electrode follows a four-one-electron surface process of Keggin-type PW. The modified electrode can be used as a nitrite sensor. Comparison of amperometric i-t curves shows that the response current of nitrite reduction at the electrode modified with PW/PV4P-g-CNTs is10-12times higher than that of CNTs at0.65V. A linear concentration of NO2-ranged from1.2to17.5μM and a detection limit of0.2μM can be observed in amperometric i-t curves at PW/PV4P-g-CNTs modifed electrode.Preparation the Pt(Ru)-CNT and Pt (Ru)-HPA-CNT. By scanning and transmission electron microscope display Pt(Ru)-CNT and Pt (Ru)-HPA-CNT pictures under electron microscopy. With the X-ray powder diffraction determination Pt(Ru)-CNT and Pt(Ru)-HPA-CNT XRD figure. Preparation the Pt(Ru)-CNT and Pt(Ru)-HPA-CNT modified in glassy carbon electrode. Determination by cyclic voltammetry Pt(Ru)-CNT and Pt(Ru)-HPA-CNT glassy carbon electrode electrochemical behavior. Through electro catalytic oxidization of methanol to contrast Pt(Ru)-CNT and Pt(Ru)-HPA-CNT catalytic effect.With assist of PMo, PtIr nanoparticles were homogeneously dispersed on the surface of MWCNTs.The size of PtIr nanoparticles can be controlled from1.6to3.2nm by tuning the composition of Pt catalysts.The preparation of PMo/Ptlr/MWCNT catalysts was optimized.It is founded that the PMo/PtIr/MWCNT catalysts prepared at Pt/Ir ratio=4have significant advantage over others, which possessed unique property such as a smaller size of PtIr nanoparticles, a higher electroactive surface area, and a larger current density of methanol oxidation. For the sake of comparison, other Pt catalysts were prepared in a controlled experiment including Ptlr/MWCNT, PMo/PtRu/MWCNT and PMo/Pt/MWCNT catalysts.In the absence of PMo, for Ptlr/MWCNT,PtIr nanoparticles were unevenly dispersed and aggregated on the surface of MWCNTs.Their sizes average3.1nm, being much larger than those of PMo/PtIr/MWCNT catalysts.Moreover, PMo/Ptlr/MWCNT catalysts show a superior behavior on the electro-oxidization of methanol as compared to other three Pt catalysts for a better CO-tolerance and a higher catalytic efficiency of methanol oxidation.