【作者】 蒋淇忠；

【导师】 林维明；

【作者基本信息】 华南理工大学 ， 工业催化， 2000， 博士

【摘要】 直接甲醇燃料电池（Direct Methanol Fuel Cell，简称DMFC）是直接利用甲醇作为阳极燃料的质子交换膜燃料电池，无需甲醇转化装置，具有系统结构简单、体积能量密度高、燃料补充方便、工作温度低、启动快等优点，特别适用于便携式移动电源、电动汽车等。本工作合成了用于直接甲醇燃料电池甲醇氧化电催化剂，探索性地制备了DMFC膜电极，设计、制备、组装了DMFC单电池系统和三电池电堆，为DMFC的实用化研究迈出第一步。 通过大量的文献查阅，选择以高导电、高比表面积的碳黑为载体的Pt基二元合金负载型催化剂作为甲醇氧化电催化剂。用H₂O₂还原法合成了Pt—Ru／C，以期替代已商品化的Johnson Matthey同类催化剂；利用Mo元素良好的抗CO中毒的能力，选择KBH₄还原法合成了Pt—Mo／C催化剂，通过循环伏安扫描以及电流—电位极化曲线测定，确定Pt—Mo／C催化剂中Pt与Mo的最佳原子比为3:1。通过循环伏安扫描发现，制备催化剂的甲醇氧化电位低于Johnson Matthey催化剂，而氧化活性与之相当，达稳定氧化电流后经过多次扫描不产生震荡。 通过对催化剂进行XRD、XPS以及TPD表征，发现，Pt-Ru／C催化剂中Pt和Ru均以氧化物形式存在，并且Pt与Ru之间还存在相互作用；Pt-Mo／C催化剂中Pt主要以零价态形式存在，而Mo则以氧化物形式出现。以甲醇、CO和CO₂为吸附质的TPD结果表明，制备催化剂具有适宜的吸附强度，导致其具有较好的甲醇氧化活性和稳定性。 摸索了直接甲醇燃料电池膜电极的制备工艺，设计、组装了单电池系统来考察阳极电极制备工艺，提出优化的工艺方法和工艺参数：30％PTFE憎水化处理碳纸；扩散层的制备采用刷涂法，其中PTFE最佳含量为5wt％；催化剂选用20wt％Pt—Ru／C，催化剂层中催化剂优化含量为0.6mgPt／cm²，Teflon—C、Nafion的最佳用量分别为0.3mg／cm²、0.5mg／cm²。 优化了单电池的操作参数。单电池性能随着工作温度上升而提高，选择80℃为考察温度；单电池膜电极有效面积为9cm²，甲醇水溶液最佳浓度为2.5M，甲醇水溶液最佳流量为0.6ml／min；随着氧气压力的升高，单电池的性能明显增强，阴极尾气排放量对电池性能影响不大。单电池输出电压为更多还原

【Abstract】 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.更多还原