The Effects On The Performance Of Pd Based Catalysts By Conducting Polymer Modified Activate Carbon Support

Improve the utilization of resource and development of new energy sources to reduceenvironmental pollution has become one of the important issues addressed by today’ssocial urgency. The fuel cell is a low pollution and high energy utilization technology.Direct formic acid fuel cell is a low-temperature liquid fuel cells, has a very broadapplication prospects. However, the commercialization of low temperature fuel cellneeds to find high activity, high stability electro-catalyst. The support of the catalystshas play a very important role for good catalysts. Vulcan XC-72R is commonly usedsupport in low-temperature fuel cell catalyst. Although Vulcan XC-72R has largespecific surface area, there are more micropores. The dynamics process on the metalparticles into the microporous is slow because of the large mass transfer resistance andthe metal particles can not be effectively used. Also activated carbon support isinstability itself, by long working hours lead to oxidation, the loss of loaded metal,eventually leading to catalyst deactivation.In this thesis support of good electrical conductivity and stablity, Vulcan XC-72Ractive carbon surface modified layer of polyaniline (PAnC), is prepared. The effects ofPd and PdAu bimetallic catalyst which use PAnC as support is further studied. Theoptimum preparation conditions of PAnC is that surfactant dosage is0.0586g, the ratioof oxidant to aniline is60:1, the ratio of activated carbon to aniline is4:1. Theproperties of the Pd catalyst as the support of PAnC which preparation condition is asabove are best. The experimental results show that when Pd: Au atomic ratio is4:1, thebehavior of the Pd4Au/PAnC catalyst is the best.X-ray diffraction (XRD), transmission electron microscopy (TEM) and other meansfor PAnC support and Pd/C,PdAu/C,Pd/PAnC,PdAu/PAnC catalysts are characterized.The experimental results confirm that the metal particles size is small and about2~4nm and disperse evenly, using PAnC as support of Pd catalyst.In addition, by cyclicvoltammetry(CV), linear sweep (LSV) and chronoamperometry (CA) combined withPotential multi-step experimental method, the activity and stability of the catalysts arediscussed.The results showed that the catalyst used the PAnC as supports having a higher activity and stability for formic acid oxidation than single used Vulcan XC-72R. WhenAu join the Pd catalyst, Pd and Au can form alloy partly, which can promote thedispersion of Pd, and formic acid oxidation on the catalyst. PAnC is proved to be anexcellent support for the electrocatalyst.