Development of Ultrasmall Manganese Oxides for Multi-Functional Applications

Abstract

Manganese oxides have attracted considerable attention as sustainable functional materials owing to their earth abundance, rich redox chemistry, and structural diversity. Particle-size engineering has emerged as an effective strategy for enhancing their electrochemical and catalytic performances by increasing surface area, shortening diffusion pathways, and modifying surface structures; in particular, ultrasmall manganese oxides exhibit physicochemical properties inaccessible to bulk materials. This account summarizes recent advances in the synthesis and applications of ultrasmall manganese oxides. A low-temperature alcohol reduction process enables the preparation of highly dispersed manganese oxide nanoparticles with controlled crystal structures and exceptionally high specific surface areas. They exhibit enhanced performance in rechargeable battery cathodes, heterogeneous aerobic oxidation catalysis, and oxygen electrocatalysis, with new physicochemical properties and mechanistic insights, offering design principles for next-generation energy-storage and (electro)catalytic materials.