Preparation, Characterization Of PtNiSnO2/C And Study On The Electrocatalytic Oxidation Of Ethanol Activities

Direct ethanol fuel cell (DEFC) is ethanol as a fuel directly to convert chemical energy into electrical energy power generation device. Ethanol as a fuel source abundant, inexpensive, high energy density(8.1 kWh/kg), is a renewable green fuel has become widely accepted. But the commercialization of DEFC is slow, the main problem is:the sluggish kinetics of the oxygen reaction at the anode side, the electrode Pt susceptible poisoning by adsorbed CO species, and the C-C of ethanol in the break little contribution, lead the complete oxidation of ethanol after 12 electrons is very difficult, and at present mechanism of electrocatalytic oxidation of ethanol is not clear, this limits the development of the catalyst system. Therefore, the preparation of low Pt, high efficiency anode catalyst, and its electrocatalytic oxidation mechanism are the difficult problems for DEFCs.The activity of the catalyst was closely related to its structure, composition, particle size and dispersion. Precious metals were prepared by halide precursor solution, due to the reduction obtained nanoparticles tend to aggregate the water solution of strong polar interaction. And preparation of nanoparticles in the organic phase, the lower polarity leads to the dispersion of catalyst of high and uniform particle size, narrow distribution, the catalytic activity of high.A low-platinum ternary anode catalyst Pt-Nix-Sn02/C(x=1/4,1/3,2/3,1) and Pt/C, Pt-Ni1/3/C, Pt-SnO2/C have been synthesized by a modified Bonnemann method.The main results are as follows:(1) Pt with face centered cubic (FCC) crystalline structure in above catalyst, all catalysts dispersion and a narrow particle size distribution, the average particle size of 2～4 nm; reveal two phases in the ternary Pt-Ni-SnO2/C catalyst:solid solution of Ni in Pt and SnO2.(2) In the geometry structure, the addition of Sn increases the lattice constant of Pt, and the introduction of Ni reduces the lattice constant, In the electronic structure, that by adding a small amount of Ni in Pt-SnO2, Pt chemical shift occurs a slight movement, Ni may change the state of the surface of Pt.(3) The catalytic activity of ethanol was changed obviously by the addition of Ni. the order of its activity is:Pt-Ni1/3-SnO2/C>Pt-Ni-SnO2/C> Pt-Ni2/3-SnO2/C> Pt-Ni1/4-SnO2/C>Pt-Ni1/3/C>Pt-SnO2/C>Pt/C, The synergy between Ni and Sn lead the EOR activity and stability of Pt-Ni-SnO2/C electrocatalyst is the better.(4) Photochemical in situ infrared spectroscopy showed that Ni and SnO2 join and did not improve the cleavage of C-C bond of ethanol, but at the low potential (< 0.4V),4 electron transfer reactions are the main, ethanol oxidation reaction pathways is still mainly on the four electron transfer reactions.