Limitations of Chronopotentiometry Test Protocols for Stability Study on Oxygen Evolution Reaction Electrocatalysts and Recommendations

The stability studies, using a rotating disk electrode under a constant current, are commonly used for the development of the oxygen evolution reaction (OER) electrocatalyst, where rise in potential with time is reported to be due to the electrocatalyst degradation. Here, we present a careful examination on the use of this technique on commercial IrO2 electrocatalysts in acidic media for a duration of 9 h. We observed that a sudden rise in the electrode potential after similar to 6 h is rather due to the glassy carbon surface-edge corrosion and detachment between carbon-catalyst interfaces. Indeed, the layer detachment generates an insulating gap between the electrode and carbon layer, resulting in an increase in the cell potential. On this regard, we examine and recommend a potentiodynamic stability test as a reliable and practical method for fast material screening and for the development of OER electrocatalysts.