Analysis of PEM fuel cell Catalyst degradation process using cyclicvoltammetry

The most frequently used techniques for oxygen reduction reaction(ORR) and hydrogen oxidationreaction (HOR) electrocatalytic studies are cyclic voltammetry (CV), rotating disk electrode (RDE),electrochemical impedance spectroscopy (EIS) and linear Sweep voltammetry (LSV), as well assteady-state polarization. All these measurements are realized in a three-electrode system, with aworking electrode loaded with the catalysts for measurement, a reference electrode, and a counterelectrode (usually a Pt wire or graphite rod). CV is the one of the most useful techniques inelectrochemistry (۱). It can quickly provide qualitative information about catalysts and electrochemicalreactions, such as the electrochemical response of catalysts, the interaction of the catalysts with theelectrolyte, and the catalytic activity of the catalysts (۲). In this work, the effect of the aging process onthe catalyst electrochemical active surface area (ECSA) is studied using CV. Fig. ۱ shows the CVresponse of Pt/C Catalyst (۲۰ wt%) in acidic and argon saturated media. In the obtainedvoltammograms the reversible peaks related to the H adsorption/desorption can be observed in ۰-۰.۳VRHE can be observed. According to the obtained results, the ECSA values are decreased by۴۱.۴۴%- ۹۰% at ۵۰ and ۲۰ mV/s, respectively. The significant decrease in ECSA and ORR half-wavepotential can be attributed to the formation of Pt oxide, Pt particle sintering, Pt dissolution/redeposition,and carbon support corrosion.