Abstract
Proton exchange membrane (PEM) water electrolyzers stand as one of the foremost promising avenues for acidic water splitting and green hydrogen production, yet this electrolyzer encounters significant challenges. The primary culprit lies in not only the requirements of substantial platinum-group-metal (PGM)-based electrocatalysts (e.g., IrO (x) ) at the anode where sluggish oxygen evolution reaction (OER) takes place, but also the harsh high overpotential and acidic environments leading to severe performance degradation. The key points for obtaining accurate stability/durability information on the OER catalysts have not been well agreed upon, in contrast to the oxygen reduction reaction fields. In this regard, we herein reviewed and discussed the pivotal experimental variables involved in stability/durability testing (including but not limited to electrolyte, impurity, catalyst loading, and two/three-electrode vs membrane-electrode-assembly), while the test protocols are revisited and summarized. This outlook is aimed at highlighting the reasonable and effective accelerated degradation test procedures to unravel the acidic OER catalyst instability issues and promote the research and development of a PEM water electrolyzer.