Fuel Cells Use Noble Metals (Pt, Au, Pd) For Preparation And Performance

With the rapid development of modern industry, the exhaustion of the nature can supply energy and environmental pollution is increasingly serious, the fuel cell as a kind of clean, efficient, safe and new energy, shows the broad and attractive prospects. On account of the rate of the cathodic oxygen reduction reaction (ORR) is much slower, compared with the anode hydroxide (HOR). In recent years, the fuel cell catalyst research mainly concentrated in the cathode catalyst, which makes the cathode still needs a lot of Pt to ensure the cathodic reaction rate. Due to the price and scarcity of platinum resources, easy to inactivation by CO poisoning, the high cost of Pt catalyst has severely limited the development and large scale commercialization of fuel-cell. Dealloyed catalyst with low Pt content and core-shell structure offers a good prospect in reducing the cost、improving catalytic performance. It can effectively reduce the Pt load and improve the utilization efficiency of Pt. In addition, we can also change the electronic structure to improve the catalytic performance of Pt through the introduction of other metals.In this paper we adopted total reduction method prepare composite bimetallic Au@Pd/MWCNTs catalyst. Transmission electron microscopy analysis suggested that Au@Pd sol nano particle size is small(-5nm), and scattered evenly. The electrochemical test results suggested that Pd/MWCNTs has better catalytic properties for the reduction of oxygen than Au@Pd/MWCNTs, and the catalytic activity of Au@Pd/MWCNTs increased with the increase of content of Pd.Different proportion of PtNi/MWCNTs catalyst was prepared by impregnation reduction method. X-ray diffractometer、Transmission electron microscopy and X-ray photoelectron spectroscopy tests show that we got the small size, uniform dispersion PtNi alloy catalyst. The electrochemical test results suggested that:In the alkaline electrolyte, the area of activity of PtNi alloy catalyst decreased with the increase of Ni content. On the contrary, in the acidic electrolyte, the area of activity of PtNi alloy catalyst increased with the increase of Ni content. But PtNi alloy catalyst has the better stability in the alkaline electrolyte than that in the acidic electrolyte.Modified Au nano sol through methyl orange, then load it on the MWCNTS, we got Au/MWCNTS catalyst. This method not only makes the functional modification of multi-walled carbon nanotubes, but also change the electronic structure of Au. Transmission electron microscopy and X-ray diffractometer analysis show that the diameter of Au nano particle is3～6nm, and the Au nano particles spread evenly. The electrochemical test results suggested that Au/MWCNTs has more excellent catalytic activity and stability. The activity for methanol oxidation of Au/MWCNTs increased with the increase of content of methyl orange...