摘要
研究了氧在载铂合金多孔电极上的阴极还原行为．这种合金催化电极在酸性介质中表现了很好的稳定性，在宽广的工作电流密度范围内，其阴极极化比传统的载铂多孔电极降低２０～４０ｍＶ．利用加速老化试验考查了催化剂粉末与催化电极的稳定性，用ＸＲＤ检测了老化前后催化剂金属成合金的晶型和颗粒度，表明该合金催化电极具有优良的抗烧结能力．老化后滤出液中铂流失量的测定同时表明，合金催化剂的抗腐蚀能力同样是卓越的．基于这些实验事实，提出了合金元素Ｆｅ和Ｃｏ对碳上Ｐｔ原子的“锚定效应”理论，圆满地解释了实验现象，为研制活性与稳定性良好的氧电极提供了理论依据．
The cathodic reduction of oxygen is studied on porous carbonbased electrodes carrying platinumiron and/or cobalt alloy catalysts. Electrodes using such electrocatalysts, particularly when used as cathodes in acidic electrolytes, remain stable for longer periods. The cathodic polarization of oxygen reduction on such electrodes is 20 mV to 40 mV lower than that on the conventional electrode on which only platinum alone is used as an electrocatalysts. An accelerated aging test (AAT) is used to evaluate the corrosion resistance and sintering resistance of each catalyst. The dissolution of the catalyst in the AAT filtrate is analysed and provides a measure of the corrosion resistance. The particle size of catalyst powders before and after AAT is determined and indicates the sintering resistance. Socalled “anchor effect” of iron and/or cobalt to platinum on carbon substrates are proposed to explain the enhanced effect of iron and cobalt in platinum alloy catalysts compared with catalysts that contain platinum alone.
出处
《电化学》
CAS
CSCD
1998年第1期42-46,共5页
Journal of Electrochemistry
关键词
燃料电池
正极
氧电极
还原
催化剂
锚定效应
Fuel cells, Porous electrodes, Oxygen reduction, Platinumironcobalt alloy catalysts, Anchor effect
