LAUSR

Electrochemical oxygen evolution reaction (OER) is an important half-cell reaction in many renewable energy conversion and storage technologies including electrolyzers, nitrogen fixation, CO 2 reduction, metal-air batteries, and regenerative fuel cells. Among them, the proton exchange membrane (PEM)-based devices possess a series of advantages such as excellent proton conductivity, high durability, and good mechanical strength, which have attracted global interest as a green energy device for transport and stationary sectors. Nevertheless, concerning the rapid commercialization, it is urgent to develop highly active and acidic-stable OER catalysts for PEM-based devices. Herein, in this review, based on the recent advances in theoretical calculation and in-situ/operando characterization, we first discussed the OER mechanism in acidic conditions in detail. Subsequently, the recent progress of a series of acid-stable OER catalysts, including noble metals, non-noble metals, even metal-free based OER materials, are systematically summarized. Finally, the current key issues and future challenges of materials towards acidic OER catalysis are identified, and potential directions are proposed as well.