Recent development of non-noble metal catalysts for the oxygen evolution reaction (OER) under different pH

With the advent of the new energy revolution, higher demands have been placed on green hydrogen production. The OER, as the anodic reaction in water electrolysis for hydrogen, involves a four-electron transfer process and has a high energy barrier. Therefore, the development of efficient OER catalysts is crucial. Though IrO₂ has been widely applied in lab research, its low abundance in the Earth's crust poses significant challenges for large-scale industrial utilization. As a result, numerous studies have been dedicated to developing non-noble metal catalysts to replace IrO₂, and it has been revealed that the pH conditions are crucial for the activity and stability of OER catalysts. Therefore, this review starts from the OER mechanisms under different pH conditions, and discusses the preparation methods, regulation strategies, and performance of non-noble metal catalysts under different pH conditions. It covers a variety of catalysts, including Co-, Ni-, Mn-, NiFe-based materials and high-entropy alloys, and introduces various regulation methods such as doping, defect engineering, morphology control, construction of heterojunction, electronic spin state regulation, and electrolyte engineering. Finally, it comprehensively assesses the application prospects of the catalysts under different pH conditions in conjunction with OER processes and equipment, providing a reference for future catalyst design and regulation engineering for OER technologies.