Investigation of Ni Catalyzed Oxygen Reduction Reaction with the Interdigitated Array Electrodes

Oxygen reduction reaction is considered as the “bottleneck” of the energy storage and utilization reactions, and understanding the specific reaction pathway and mechanism are essential in designing new catalysts. Interdigitated array electrodes are special electrochemical tool for in situ measurements and have the advantage of high collection efficiency and high sensitivity, which could be utilized for the detection of the reaction intermediate. Here in this work, the nonprecious metal catalyst Ni was studied in situ towards the ORR catalytic activity with IDA electrodes. Through the electrodeposition method, the Ni catalyst was conducted with the IDA electrodes successfully. The generator-collector mode of IDA electrodes was applied so as to carry out ORR and have the reaction intermediate H 2 O 2 being detected simultaneously. It was observed that the average electron transfer number of Ni-catalyzed ORR is about 3, and it various with the change of applied potential and the surface state of catalyst. The H 2 O 2 production changes between 40% and 75%, reflecting the possible reaction pathway at different status. After being annealed with different temperatures, the overall catalytic current enhanced with the increase of temperature, while the average electron transfer number declined.