Enhanced Oxygen Reduction Performance on {101} CoMn2O4 Spinel Facets

We present a facile colloidal synthesis method to produceuniform-sized(9 nm) CoMn2O4 spinel nano-octahedra tailoredwith {101} facets. These nano-octahedra demonstrate enhanced electrocatalyticactivity for the oxygen reduction reaction (ORR) in alkaline mediacompared to their spherical counterparts and previously reported spinelelectrocatalysts. At 0.85 V, they achieve a high mass activity (MA)of 60.0 A/g, surpassing their spherical counterparts (38.6 A/g). Moreover,the CoMn2O4 nano-octahedra exhibit favorablestability, maintaining an MA of 47.2 A/g after 10 000 durabilitycycles. This work highlights a promising approach for synthesizingadvanced spinel nanooxides with controlled crystal facets, which holdthe potential to serve as nonprecious metal ORR electrocatalysts.The enhanced ORR performance is attributed to the exposed active catalystsurfaces in the well-defined structures of the nano-octahedra, emphasizingthe significance of catalyst shape control.