Interfacial electronic coupling in Mn3O4/C@FeOOH nano-octahedrals regulates intermediate adsorption for highly efficient oxygen evolution reaction

Exploiting high-efficient low-cost metal-based electrocatalysts for oxygen evolution reaction (OER) in alkaline media is still urgent and challenging. Herein, a hierarchical nanostructure of manganese oxide/carbon@iron oxyhydroxide (denoted as Mn3O4/C@FeOOH) nano-octahedrons via a three-step approach. The optimal electrocatalyst Mn3O4/C@FeOOH was achieved and delivered a low overpotential of 295 mV at 10 mA cm-2, a small Tafel slope of 47.6 mV dec- 1 and a decent stability toward long-term electrolysis of 16 h with only 2.2% degradation. The excellent OER performance of the hybrid Mn3O4/C@FeOOH could be attributed to the synergistic effects of the individual counterparts, namely, the structural support of the amorphous carbon skeleton to maintain the integrity of microstructures, the enhanced conductivity imparted by the uniformly dispersed Mn3O4 and graphite nanoparticles, and the partial electron redistribution between the Mn3O4/C and FeOOH interface, optimizing the adsorption/desorption of intermediate oxygenated species. This work provides a novel strategy to prepare an efficient and stable electrocatalyst for OER in alkaline media.

Automated summary

This study presents a hierarchical nanostructure of manganese oxide/carbon@iron oxyhydroxide (Mn3O4/C@FeOOH) as an efficient and stable electrocatalyst for oxygen evolution reaction (OER) in alkaline media. By optimizing the structure and composition of the electrocatalyst, a low overpotential, small Tafel slope, and good long-term stability were achieved. The superior OER performance of the hybrid Mn3O4/C@FeOOH was attributed to the synergistic effects of the individual components, including the structural support of the amorphous carbon skeleton, enhanced conductivity from uniformly dispersed Mn3O4 and graphite nanoparticles, and partial electron redistribution at the Mn3O4/C and FeOOH interface.