Optimizing oxygen evolution/reduction reaction processes via anion vacancy engineering

Abstract

The increasing global energy demand and environmental challenges have highlighted the need for efficient, sustainable energy conversion technologies, particularly those involving the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). These reactions are crucial for electrochemical devices like water splitting, fuel cells and metal-air batteries, but their high overpotentials and energy requirements limit widespread application. Noble metal catalysts, though effective, are costly and scarce, prompting interest in transition metal alternatives. Anion vacancy engineering has shown promise in enhancing these catalysts’ performance. This review covers recent advancements in anion vacancy engineering for OER and ORR electrocatalysis, discussing fundamental mechanisms, strategies for creating anion vacancies (e.g., solution etching, plasma treatment), advanced characterization techniques (e.g., EPR, PAS, XPS), and how anion vacancies enhance catalytic performance through optimizing intermediate adsorption/desorption, improving metal-support interactions, facilitating catalyst reconstruction and so on. Challenges remain in precisely controlling anion vacancy synthesis, scaling up production, and understanding real-time structural changes in vacancy-rich catalysts. Future research should focus on novel synthesis techniques, in situ characterization methods, and leveraging machine learning to optimize these catalysts. This review aims to guide the development of efficient, sustainable energy conversion technologies using vacancy-engineered electrocatalysts.