Engineering oxygen-evolving catalysts for acidic water electrolysis

The utilization of water electrolysis for green hydrogen (H2) production, powered by renewable energy, is a promising avenue for sustainable development. Proton-exchange-membrane water electrolysis (PEMWE) stands out as one of the most efficient H2 production technologies. However, implementing it on an industrial scale faces substantial challenges, particularly regarding the oxygen evolution reaction (OER). The OER, a critical process with inherently slow kinetics requiring additional potential, significantly influences overall water-splitting efficiency. Most OER electrocatalysts in PEMWE struggle with poor stability in harsh acidic environments at high oxidative potentials. While rare-earth metal oxides, such as iridium or ruthenium oxides, offer stability in commercial oxygen-evolving electrocatalysts (OECs), their use depends on achieving economically and sustainably viable operations. An alternative approach involves developing low- or non-noble metal-based OECs with sustaining high activity and long-term durability. Although such materials currently exhibit lower activity and stability than noble-based OECs, notable progress has been made in enhancing their performance. This review provides an overview of recent advancements in designing acidic-stable OECs based on low or without noble metal contents. It delves into the thermodynamics and degradation mechanisms of OECs in acidic media, evaluation parameters for activity and stability, strategies for developing active and acid-stable OECs, and the challenges and opportunities of acid water electrolysis. Through a detailed analysis of these aspects, the review aims to identify opportunities for engineering actively durable OECs.