Study of alcohol electrooxidation mechanism at nano-particle electrocatalyst by using integrated powder microelectrodes

到目前为止，电催化剂的研究包括两类；一个是基于pt板电极的基础研究，另一个是基于pt负载碳的单电池特性研究。本报告拟采用不受粘结剂聚合物影响的粉末微电极，直接研究用于直接酒精燃料电池（DAFCs）的粉末电催化剂上的酒精电氧化机理。本文研究了一种载铂碳（Pt/C）电催化剂，并将其填充到粉末微电极的微腔中，以方便、准确地测量酒精氧化活性。调查的主题总结如下。采用Pt/C或Pt- ru /C填充粉末微电极，测量了C_1-C_4醇氧化在高温加压条件下的I-V曲线。此外，还制备了粉末微电极与微圆盘电极结合的双微电极，后者的集电极成功地检测了前者产生电极上醇氧化反应的产物。此外，通过开发分析设备，研究了膜电极组件产生的反应产物/中间体，以阐明反应途径。在此基础上，制备了电化学固态半电池，研究了水溶液体系和质子交换膜基固体体系中醇氧化反应的差异。总之，通过设计新的电极体系来评价dmfc中使用的功能材料，大大提高了粉末电催化剂和基于电催化剂的电池体系的电化学研究。

Thus far, electrocatalyst investigations have consisted of two categories ; one is Pt-plate electrode-based fundamental study and the other is Pt-loading carbon-based single-cell characteristic study. The present report is planned to study alcohol electrooxidation mechanism directly at powder electrocatalysts for use in direct alcohol fuel cells (DAFCs) by employing a powder microelectrode without any influence of binder polymer. We have focused our attention on an electrocatalyst of Pt-loading carbon (Pt/C) and filled it to the microcavity of the powder microelectrode to measure the alcohol oxidation activity easily and precisely. Investigated topics are summarized as follows. Powder microelectrode filled with Pt/C or Pt-Ru/C is utilized to measure I-V curves of C_1-C_4 alcohol oxidation under elevated temperature and pressurized conditions. In addition, a dual microelectrode of powder microelectrode combined with microdisk electrode was fabricated, in which the latter collector electrode successfully detected the reaction product of alcohol oxidation at the former generator electrode. Moreover, reaction products/intermediates produced at the membrane-electrode assembly was investigated in order to clarify the reaction pathways, by developing analyzing equipment. Furthermore, electrochemical solid-state half cell was fabricated to investigate the difference of alcohol oxidation reactions between aqueous system and proton-exchange-membrane-based solid system. In conclusion, by designing new electrode system to evaluate the functional materials used in the DMFCs, electrochemical studies for the powder electrocatalysts and the electrocatalyst-based cell systems have been greatly improved.