Designing and regulating catalysts for enhanced oxygen evolution in acid electrolytes

The proton exchange membrane (PEM) water electrolyzer has been considered a versatile approach for practical H₂ production. However, the oxygen evolution reaction (OER) in acid media with complicated proton-coupled electron transfer steps possesses sluggish kinetics and high reaction barriers, severely hindering the development of PEM water electrolyzers. Consequently, high-efficient Ru- and Ir-based catalysts have always been essential to accelerate the OER rate and lower the reaction barrier in PEM water electrolyzer. Therefore, it is very necessary to construct low-cost catalysts with excellent electrocatalytic performances to replace these noble metal-based OER electrocatalysts. In this review paper, a detailed discussion towards fundamentally comprehending the reaction mechanisms of OER was conducted. Accordingly, we proposed the principles of designing advanced OER electrocatalysts with enhanced performances and lowered costs. After that, recent developments in designing various acidic OER electrocatalysts were summarized. Meanwhile, the available regulation strategies about noble metals, nonprecious metals, and metal-free nanomaterials were presented, which are promising for tuning the electronic structures, boosting the electrocatalytic performances, and reducing the costs of electrocatalysts. We also provided the existing challenges and perspectives of various OER electrocatalysts, hoping to promote the development of PEM water electrolyzers.