A roadmap towards sustainable anode design for alkaline water electrolysis

Long-term anode durability with high intrinsic activity is crucial to deliver affordable green hydrogen by electrochemical water splitting. Current research mainly focuses on tuning the oxygen evolution reaction activity and efficiency, although the anode's structural, chemical, and mechanical sustainability at high geometric activity poses a significant challenge. In this review, anode degradation mechanisms based on surface reconstruction, agglomeration, and dissolution are described and discussed various strategies to design a durable anode with synergistic modulation of intrinsically reactive abundant active sites, efficient mass transfer, the fast rate for electron transportation, and gas evolution. Various strategies such as electronic modulation by cation, heteroatom doping, surface and structural optimization by defects engineering, heterostructure development and morphology tuning, aerophobic character, and strong catalyst support interactions are evaluated. Finally, we discussed the remaining stability challenges and set practical guidelines on how these potential strategies can be exploited to design stable high-output OER catalysts. With these insights, this review article will hopefully provide a roadmap for the rational design of a sustainable anode to make the water electrolysis process viable for scalable hydrogen production.