A convenient protocol for the evaluation of commercial Pt/C electrocatalysts toward oxygen reduction reaction

Abstract

Thin-film rotating disk electrode (TF-RDE) method has been routinely used to evaluate electrochemical active surface area (ECSA) and mass activity (MA) of an electrocatalyst toward oxygen reduction reaction (ORR), since it is relatively simple, materials-saving, and can predict the performance of an electrocatalyst in membrane electrode assemblies (MEAs). However, previously suggested protocols are complicated and time-consuming, relevant to several important test parameters unspecified. Currently, we still confront the dilemma of incomparable electrochemical performance of the same commercial Pt/C reported by different laboratories, assuming that different batches of commercial Pt/C are basically consistent with one another. Herein, we report a convenient protocol for the evaluation of commercial Pt/C using ethanol based ink formulation, short ink dispersing duration, and fast ink droplets drying method together with scrutinizing several critical yet unspecified factors, including chloride, nitrate, water purity, flow rate of N2 and O2, temperature, and the loading of platinum on RDE. Finally, the ECSA and MA values of three commercial Pt/C were examined by at least ten independent measurements for each electrocatalyst by using optimized test parameters to verify the accuracy and reproducibility. We expect this study would be beneficial for accurate, repeatable, fast, and comparable assessment of ORR electrocatalysts.