Electrocatalytic Measurement Methodology of Oxide Catalysts Using a Thin-Film Rotating Disk Electrode

Abstract

Transition-metaloxides can exhibit high electrocatalytic activity for reactions such asthe oxygen reduction reaction (ORR) in alkaline media. It isoften difficult to measure and compare the activities of oxidecatalysts on either per mass or per surface area basis,because of the poorly defined oxygen transport to and withinporous oxide electrodes of several tens of micrometers thickness. Inthis study, a methodology was developed to compare the ORRactivities of submicrometer-sized transition-metal oxides. Thin films of LaNiO3, LaCu0.5Mn0.5O3,and La0.75Ca0.25FeO3 oxide particles were bonded to glassy carbon viaan ion-exchanged Nafion binder, and their mass and specific ORRactivities were extracted from rotating disk electrode measurements. We foundthat the specific activity of LaNiO3 was much higher thanthat of La0.75Ca0.25FeO3 and LaCu0.5Mn0.5O3. The projection of LaNiO3 inthe actual fuel cell cathode was presented, which was shownto be competitive with current platinum-based cathodes. ©2010 The Electrochemical Society