Basis Study On Direct Methanol Fuel Cell

Direct Methanol Fuel Cell (DMFC) was one of the Proton Exchange Membrane Fuel Cell with methanol as anode fuel, which had the advantage as following: no methanol reformer, simple system structure, high ratio volume energy density, convenient fuel supply, low working temperature, quick start and so on. It especially was suitable for mobile power, electric vehicles and other application. Anode catalysts for methanol oxidation used in DMFC were synthesized in our research. As the first step of future application, we exploringly prepared the membrane electrode assembly used in DMFC, then designed and installed DMFC single cell system and three cells stack system which should be the first local one.According to the lots of reference, the Pt based bimetallic alloy catalysts supported on carbon black with high electric properties and surface area were selected as anode electrocatalysts. Pt-Ru/C catalyst was prepared by H₂O₂ reduction in order to replace the commercial catalysts from Johnson Matthey Co. Ltd. On the basis of well CO tolerance properties of Mo, Pt-Mo/C catalysts were synthesized by KBH₄ reduction. The catalyst in which Pt: Mo atomic ratios was 3:1 showed better performance from the cyclic voltammetry (CV) curve and current-potential polarization results. It was found: although their electrochemical activity were similar, the methanol oxidation potential of in house catalysts were lower than that of Johnson Matthey catalyst, and CV curve of in house catalysts didn't vibrate after much scanning after the oxidation current is stable.The XRD, XPS and TPD were performed to know the physical and chemical properties of catalysts. It was discovered as following: there were Pt oxide and Ru oxide in Pt-Ru/C and interaction between Pt and Ru. Pt existed as zero value in Pt-Mo/C whereas Mo existed as Mo oxide. The TPD results with methanol, CO, CO₂ as adsorbates showed that in house catalysts had the suitable adsorption intensity, which resulted in their better methanol oxidation activity and stability.After preparation ways of membrane electrode assembly (MEA) of DMFC and anode electrode were studied by single cell system, the optimized preparation ways of anode electrode were issued: hydrophobic carbon papers were prepared with 30%PTFE.