Preparation And Characterization Of Nano-Pt/SiC And Electrocatalytic Oxidation

Lower temperature fuel cells have always been a hot point for researchers, as they are possession of the advantages of abundant fuel source, high energy density, the ability to run at room temperature and high stability. At present, the study of fuel cells focuses on the following parts:acquirement catalysts with high performance, preparation of efficient membrane, optimization of the whole fuel cells system, etc. Among the above aspects, the electrode catalyst plays an essential role, which restricts the development of the fuel cells. A large number of researches have showed that the activity and stability of the catalyst have been affected by the supports of the catalyst, the alloy which made up of different materials and the preparation methods, and so on. So far, Pt and Pt-based catalysts have been thought to be the most effective catalysts, for example, PtRh, PtRu, PtPd, PtSn, among which PtRu is the best one. Although carbon is most widely used as the support of the electrode catalyst, it can be easily eroded under the high temperature, high pressure, high potential and high oxygen environment, which would lead to loss of Pt metal particles, damage of the electrodes and reduce the lifetime of the cell. SiC is recently discovered to be a support for the catalysts due to its good thermal conductivity and chemical stability.In this paper, we preparation of Pt/SiC catalyst and studied the electrochemical characterization of the catalyst using the XRD and CV technique. The result shows that catalyst that based on SiC support has better catalysis than which based on C-support. What is more, under the environment of hydrogen, the activity of the SiC-based catalyst reduced under 400℃is higher.Also, we prepared PtRu alloy by the combination of the ultrasonic dispersion and the hydrogen reduction, and tested it by the XRD and CV. We can draw conlusions from the experience data:the activity of the RuPt/SiC catalyst has been greatly improved, thus it has the better corrosion resistant and poison resistance. The RuPt catalyst has the better activity, stability and poison resistance when the precursor of the RuPt/SiC is calcined at 300℃for 2h, while the ration of Pt and Ru is 1:1. In addition, we studied the preparation of the different morphologies of SiC by the sucrose and phenolic resin as carbon source and the TEOS as silica source. Then it is used as support to synthesis Pt/SiC catalyst by ultrasonic dispersion and the hydrogen reduction. The results of the CV showed that the morphologies have great influence on the electrochemical oxidation of small organic molecules and hydrogen absoption/desorption.