Recently developed direct methanol fuel cell (DMFC) has been received widespread attention due to the abundant source, the low price, the safety of the storage and transportation of the fuel. However, some problems, such as low electrocatalytic activity of the anodic catalyst restrict its practical use. In this thesis, in order to reducing the amount of the Pt catalyst and improving the electricatalytic activity of the Pt catalysts, the solid phase reaction method and organosol method were used to prepare the Pt/C catalysts with high dispersibility and utramicro particles. Using the XRD and TEM techniques, the size and crystallinity of the Pt particles prepared with different methods were studied. The electrocatalytic activities and stability for the methanol oxidation were evaluated with the electrochemical techniques. The main results obtained are as follows:1. The Pt/C catalyst with 20% Pt was prepared with the solid phase reaction method. The size of Pt particles, the utility of the electroactive specific surface area of Pt, and the electrocatalytic activities and stability for the methanol oxidation for the Pt/C catalyst prepared with the solid phase reaction method are slightly better than that of the E-TEK Pt/C catalyst. They are much better than that of the Pt/C catalyst prepared with the traditional liquid phase reaction method. For example, for the Pt/C catalyst prepared with the solid phase reaction method, the diameter of the Pt particles is 3.7?.5nm, the utilization ratio of Pt is 15.2%, the electrochemical active surface area is 36.1m2/g. In the cyclic voltammogram obtained in the 0.5mol/L CH3OH + 0.5mol/L H2SO4 solution, the peak current for methanol oxidation is about 11.3mA/cm2 when the temperature is 30癈, the scan rate is 50mV/s, Pt loading is 28jj.g/cm2. After 6h discharge at the constant current of 50mA/cm2 at 65癈, the overpotential of the Pt/C catalyst-Nation membrane electrode increases onlyl 7mV. While for the Pt/C catalyst prepared with the liquid phase reaction method, the diameter of the Pt particles is 9.0+ 1.5nm, the utilization ratio of Pt is 3.62%, the electrochemical active surface area is 8.60m2/g. Thepeak current for methanol oxidation is about 6.85mA/cm2. After 6h discharge at the constant current of 50mA/cm2, the overpotential increases 240mV.2. The stable Pt colloid was prepared using SnCl2 as the reductant in the organic medium and then dispersed on the active carbon, obtaining the colloidal Pt/C catalyst with 20% Pt. The size of Pt in the colloidal Pt/C catalyst is 3.8?.3nm. The utilization ratio of Pt is 13.69%. The electrochemical active surface area is 32.52m2/g. In the cyclic voltammogram obtained in the 0.5mol/L CH3OH + 0.5mol/L H2SO4 solution, the peak current for methanol oxidation is about 11.0mA/cm2 when the temperature is 30癈, the scan rate is 50mV/s, Pt loading is 28ug/cm2. The electrocatalytic activity for the methanol oxidation of the colloidal Pt/C catalyst obtained with organosol method is similar to that of the Pt/C catalytic prepared with the solid phase reaction method. However, the preparation technique of the colloidal Pt/C catalyst is simple, stable and suitable for the production on a large scale. |