Research On New Style Nanomaterials In Fuel Cell Electrode

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 easy 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 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 Pt-Ru/CMK-3 catalyst 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 solution 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 solution of THF and H2O are similar. Thus, H2PtCl6 and RuCl3 can be reduced almost at the same time, leading that the Pt-Ru/CMK-3 catalyst prepared possesses high alloying extent. It was found that the alloying extent is not related to the volume ratio of THF and H2O in the solution. In addition, THF and H2O can form the molecular cluster due to the formation of the hydrogen bond between THF and H2O.2. The Pt/CMK-3 anode catalyst for direct methanol fuel cells (DMFC) was prepared by the liquid reduction method using paraformaldehyde as the reducing agent. The results showed that CMK-3 is a highly intriguing support material for DMFC due to its high surface area, uniform mesopore, and high thermal and chemical stability. The average particle size of Pt nanoparticles in Pt/CMK-3 was 2.8 nm, which was smaller than the commercial Pt/XC-72 catalyst from E-TEK Corp. and the Pt/C-M catalyst prepared using methanol as the reducing agent, and the particle size distribution was narrow, and the relative crystallinity was low. The electroactivity of Pt/CMK-3 for ethanol oxidation was studied. The results showed that the Pt/CMK-3 catalyst possessed the bigger electrocatalytic activity than that of Pt/XC-72 and Pt/C-M catalysts.