PEMFC电极中表面扩散现象的初步研究  

Studies of Surface Diffusion in PEMFC Electrodes

作　　者：罗江水[1,2] 陈剑[1] 衣宝廉[1] 查全性[3] 张华民[1] 

机构地区：[1]中国科学院大连化学物理研究所燃料电池关键材料与技术研究组,辽宁大连116023 [2]中国科学院研究生院,北京100039 [3]武汉大学化学与分子科学学院,湖北武汉430072

出　　处：《电化学》2008年第4期369-372,共4页Journal of Electrochemistry

摘　　要：制作双催化层结构的PEMFC电极.该双催化层由含有Nafion的内催化层、无Nafion的外催化层组成.循环伏安测试表明,未与Nafion直接接触的外催化层Pt/C催化剂也参与发生在"Pt/Nafion"界面氢原子的吸脱附反应和Pt表面含氧粒子的电化学氧化还原.当电势扫描速率较低时,未与Nafion直接接触的外层Pt/C催化剂,其对氢脱附电流的贡献和直接与Nafion接触的内催化层的Pt/C催化剂大致相当.以双催化层电极作PEMFC阴极,单电池(PEMFC)极化曲线测试表明,其阴极外催化层能明显地提高该单电池在活化极化区的输出性能.进一步证明了PEMFC阴极外催化层不与Nafion直接接触的Pt/C催化剂可通过其表面吸附含氧粒子的表面扩散参与发生在"Pt/Nafion"界面氧的电化学还原反应.上述实验为设计PEMFC电极提供了一定的新思路.A PEMFC electrode consisting of dual-layer catalyst layer （CL） was fabricated in this work. The outer CL was Nafion-free, while the inner CL was Nafion-bonded. The effects of Pt/C catalyst in the outer CL that did not contact with Nation on the current generation in PEMFC electrodes were investigated. Cyclic voltam- metric studies indicated that the Pt/C catalyst in the outer CL without direct contact with Nafion was still electro- chemically active in taking part duction of the oxygen-containing in the adsorption/desorption of hydrogen and the electrochemical oxidation/respecies occurring at the interface of ＂Pt/Nafion＂ in the inner CL. The polarization curves showed that the output voltage of the single cell was enhanced obviously by the outer CL when the current density was lower than 0.2A/cm2. The phenomena indicated that the Pt/C catalyst without direct contact with Nation also participated in the electrochemical reduction of oxygen at the interface of ＂Pt/Nafion＂ via the surface diffusion of the adsorbed oxygen-containing species.

关 键 词：PEMFC 表面扩散 成流机理 氧还原反应 阴极催化层 

分 类 号：TM911.4[电气工程—电力电子与电力传动]