Synergistic structural engineering of hierarchically porous MnCo₂O₄@MnS nanowire arrays for oxygen evolution...

Electrochemical water splitting, a promising route for sustainable hydrogen production, faces significant challenges due to the slow kinetics of the oxygen evolution reaction (OER), a four-electron transfer process. Manganese-based catalysts, with their Earth-abundance and tunable electronic structures, hold potential for the OER, but their practical application is limited by poor conductivity and low active site density. Herein, we address these issues by the surface modification of MnCo₂O₄ nanowire arrays: oxygen plasma etching enhances surface roughness and oxygen vacancy concentration, followed by controlled MnS nanoparticle deposition to form a core-shell heterostructure (p-MnCo₂O₄@MnS). Key parameters include surface structure regulation and dynamic tuning of Mn²⁺/Mn³⁺/Co²⁺/Co³⁺ ratios, which critically influence catalytic performance. The results show that plasma etching increases active sites and mitigates Jahn-Teller distortion, while the MnS shell optimizes the adsorption energy of *OOH/*O intermediates via interfacial charge redistribution. The composite exhibits an overpotential of 290 mV at 10 mA cm^-2, which is better than those of conventional OER catalysts. This work shows synergistic effects of surface modification and structural optimization, advancing high-efficiency sustainable energy technologies.