The Acceleration On The Performance Of Fuel Cell Anode Catalyst Support By Polyaniline Doped

For the past years, conductive polymer materials have been more and more widely used in electric catalyst support, because of their conjugated electronic structure, well conductivity and stability. Among them, polyaniline, with excellent environmental stability and conductivity, can greatly improve the activity and stability of the electrocatalyst support for the alternate nitrogen atoms and benzene rings on its main chain.In this thesis, the composited support(PAnC) with conductive polymer polyaniline and activated carbon was prepared. Then, the composited support was doped with sodium dodecyl sulfate and sodium dodecyl benzene sulfonate, respectively. And the influence of the doping amount to the performance of the composited support was studied. The corresponding catalysts were obtained by loading palladium, gold and platinum on them, and the properties of electrocatalytic oxidation for formic acid, methanol and ethanol on the prepared catalysts were studied. The characterization of supports and catalysts was investigated by scanning electron microscope(SEM), transmission electron microscope(TEM), X-ray diffraction(XRD), surface area measurement(BET) and electrochemical specific surface area(ESA). The electrochemical properties of the catalysts were studied by the cyclicvoltammetry(CV), chronoamperometry(CA) and electrochemical impedance spectroscopy(EIS). In addition, the influence of different methods for the platinum catalyst preparation was studed.The results show that the catalytic performance of the Pd catalyst prepared with PAnC as a support is better than that of the catalyst prepared with activated carbon alone. In addition, the polyaniline carbon support(PAnC-S), which prepared with doping sodium dodecyl sulfate, owns more prominent electrical conductivity, more appropriate pore structure and larger surface area than that of PAnC. PAnC-S and PAnC have uniform particle sizes of about 30 nm. The TEM results showed that particle sizes of PdAu/PAnC are smaller, and metal particles on the surface of support dispersed more evenly than that of Pd/PAnC.The electrochemical results show that the polyaniline carbon supported catalysts doped with 0.2 g sodium dodecyl sulfate and 0.05 g sodium dodecyl benzene sulfonate, respectively, have the highest activity and stability for formic acid electrooxidation. So the most suitable doping amounts are determined. The Pd catalysts prepared with PAnC-S and PAnC support have larger electrochemical surface area, higher activity and stability for formic acid electrooxidation, which compared with that prepared with activated carbon alone. The platinum catalysts prepared with thermal reduction process by microwave have higher activity and stability for methanol and ethanol electrooxidation, when compared with that prepared with thermal reduction process.