Research On New Style Materials In Direct Alcohol Fuel Cell Anode Catalysis

Direct methanol fuel cell (DMFC) possesses the wide application prospect as the power source in the portable electronic products and electric vehicle etc., due to the facilitated transportation and storage of the fuel, light weight and small volume, inherent simplicity of the structure, the high energy efficiency and low pollution. However, at present, the poor kinetics of the anodic reaction of the commonly used fuel and methanol crossover are the two key techinique issues hindering the commercial application of DMFC. In this dissertation, a novel preparation method and new materials of the anodic catalysts was investigated and the effects of the several preparation variables and various new carbon materials on the alloying extent, the average size, the relative crystallinity and the distribution of the metal particles and the electrocatalytic activity and stability of the anodic catalysts were studied. The main results obtained are as follows:1. The preparation of the anodic catalyst Pt-Ru/CMK-3 using the complex reduction method and the electrocatalytic activity of the Pt-Ru/CMK-3 catalyst prepared for the methanol oxidation were investigated. It was suggested that when the Pt-Ru/CMK-3 catalyst is prepared with the complex reduction method, the mixture of tetrahydrofuran (THF) and H2O is used. Because THF can form the complex with H2PtCl6, the reduction potentials of H2PtCl6 and RuCl3 in the mixture of THF and H2O are close. Thus, H2PtCl6 and RuCl3 can be reduced almost at the same time, leading that the prepared Pt-Ru/CMK-3 catalyst possesses high alloying extent. In addition, THF and H2O can form the molecular cluster due to the formation of the hydrogen bond between THF and H2O. Because the molecular cluster of THF and H2O is large, it could prevent Pt-Ru particles from the aggregation. Therefore, the average size of the Pt-Ru particles in the Pt-Ru/C catalyst prepared with the complex reduction method is smaller than that prepared in the water. Based on the above factors, the electrocatalytic activity of the Pt-Ru/C catalyst prepared with the complex reduction method for the methanol oxidation is higher than that of the Pt-Ru/C catalyst prepared in the water.2. The performance of different carbon supported Pt-Ru (Pt-Ru/C) as an anode catalyst has been investigated. The Meso-Macroporous structured carbon can not only provide mesopores for catalytic action and adsorption, but also the macropores for transmission of materials. The prepared Pt-Ru/Meso-Macroporous structured carbon has the smaller average size, relative crystallinity, and higher electrocatalytic activities for the oxidation of methanol.3. It was found that the electrocatalytic activities of the Pt-Ru/CMK-3 catalyst prepared with the complex reduction method for the oxidation of ethanol are much higher than that of the commercial E-TEK Pt-Ru/C catalyst, illustrating that the increase in the alloying extent of the Pt-Ru particles in the Pt-Ru/C catalyst is favorable for increasing the electrocatalytic activities of the Pt-Ru/C catalyst for the oxidation of ethanol.