The Synthesis And Electro-catalytic Research Of Pd Based Nanoporous Composite Material

Because of the exhaustion of the fossil fuels and the environmental crisis,people have paid more attention to find a kind of clean renewable energy.The direct methanol fuel cell?DMFCs?are promised to be a suitable alternative energy source for portable devices due to their relative high energy density,low operating temperature and low pollutant emission.Moreover,Hydrogen?H₂?,as a clean,affluent and substitute for contaminated fuel,is being overwhelmingly pursued.Pt and its alloys are the most efficiency catalysts in the field of fuel cell and electrolysis of water,but there are still some disadvantages which limit the extensive applications,such as high cost and low CO tolerance.Thus,some researchers have been focused on the non-Pt catalysts.In this paper,a series of nanoporous Pd/CuO/xTiO₂?np-Pd/CuO/xTiO₂?hybrid catalysts were fabricated by a chemical dealloying method with a simple chemical deposition.These catalysts were characterized using scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X-ray diffraction?XRD?,and X-ray photoelectronspectroscopy?XPS?.Thecyclicvoltammetry?CV?and chronoamperometry?CA?tests were carried out to determine the electro-oxidation properties.The np-Pd/CuO/160Ti O₂ shows superior activities for the oxidation of small organic molecules and the corresponding current densities are 2.86 mA cm^-2,7.05 mA cm^-2and 9.93 mA cm^-2for the electro-oxidation of methanol,ethanol and formic acid,respectively.A probable bifunctional mechanism was suggested as:TiO₂nanoparticles would act as a supplementary material,and oxygen-containing groups generated on the Ti O₂ surface could promote oxidation of the toxic intermediates.In addition,the catalytic stability of catalysts was investigated by typical electrochemical methods.The np-Pd/CuO/160TiO₂ catalyst also exhibited good long-term stability.A novel and facile dealloying method is developed to synthesize a amorphous flower-like nanoporous PdCuNi-S electrocatalyst.It is found that after the sulfurization of PdCuNi sample,the as-obtained flower-like nanoporous PdCuNi-S catalyst receives more exposed active sites and possesses superior catalytic activity for the hydrogen production reaction in acidic media.The catalyst exhibits an onset overpotential at only-33 mV and a Tafel slope of 34 mV dec^-1.In addition,the stability test of the catalyst is conducted by a large number of cycles and long-time electrolysis,confirming the excellent durability of the catalyst.