Development of an electrochemical system to measure high-temperature oxygen reduction for the electrochemical evaluation of Pt/C and non-precious metal catalysts

In polymer electrolyte fuel cells, the oxygen reduction reaction (ORR) rate increases at high temperatures. Therefore, ORR catalysts must be designed for use at high temperatures and require evaluation. To address the problem of decreased dissolved oxygen concentrations in conventional channel flow double electrode (CFDE) systems, this study develops a CFDE system capable of electrochemical measurement at 120 degrees C that can evaluate the ORR activity of Pt-supported carbon (Pt/C) and carbon-based non-precious metal catalysts (NPMC). The ORR activity increased with an increasing reaction temperature, regardless of the catalyst, and the current density ratios at 120 degrees C and room temperature were estimated to be 2.4 and 5.4 for Pt/C and NPMC, respectively. This indicates that the NPMC ORR activity increased significantly with the increasing reaction temperature. This increased activation energy, which is approximately 2.3 times greater than that of Pt/C at the overpotential of 0.38 V, contributes to a significant increase in the ORR activity at higher temperatures.