Recent advances in the rational design of alkaline OER catalysts: from electronic structures to industrial applications

Oxygen evolution reaction (OER), as the pivotal half-reaction in electrochemical water splitting, is the main bottleneck in the widespread application of water electrolysis due to the low energy efficiency caused by the sluggish kinetics of the four electron-coupled proton transfer process. Over the past decade, tremendous efforts have been made in developing advanced OER catalysts. Clarifying the underlying origins of the slow kinetics, the structure–activity relationship is essential for designing OER catalysts. In this review, we aim to first comprehensively understand the electronic structures of catalysts involved in different mechanisms. We then discuss the origin of the scaling relation in the adsorbate evolution mechanism (AEM); further, the development on predicting and screening catalysts based on e_g orbital occupation and d-band center descriptors along with strategies beyond the scaling relationship is reviewed. Furthermore, we summarize the state-of-the-art strategy to develop catalysts by surface/interface engineering. Finally, the industrial progress and issues in exploiting OER catalysts to split water are summarized and analyzed. Through this comprehensive overview, we provide insights into designing alkaline OER catalysts from their fundamental electronic structures to industrial applications.