Manganese-containing electrocatalysts for sustainable acidic oxygen evolution

Proton exchange membrane water electrolysis (PEMWE) is recognized as an advanced technology for green hydrogen production and renewable energy conversion. However, the prohibitive cost and limited availability of precious-metal catalysts for the oxygen evolution reaction (OER) hamper its industrial application, and it is imperative to reduce the precious-metal loading by incorporating other elements or exploring alternative materials. Given the low cost and abundant reserves, manganese (Mn)-related catalysts have garnered increasing attention. This review systematically summarizes the progress of Mn-containing catalysts for acidic OER. Initially, we present an overview of fundamental characteristics and OER performance, especially the excellent stability, of Mn oxides. Then, we introduce the modulating effect of Mn in terms of the support, electronic structure, reaction mechanism, and surface reconstruction, followed by an analysis of the advancement of Mn-containing catalysts in PEMWE. Finally, the unresolved issues and future research directions for Mn-containing catalysts in acidic OER are critically discussed.