Stabilizing Polyoxometalate for Enhanced OER Performance Using a Porous Manganese Oxide Support

The oxygen evolution reaction (OER) is a critical challenge in electrocatalytic water splitting, hindered by high energy demands and slow kinetics. Polyoxometalates (POMs), recognized for their unique redox capabilities, structural archetypes, and molecular precision, are promising candidates for the oxygen evolution reaction (OER). Yet, their application is hindered by high water solubility, causing rapid degradation and efficiency loss under harsh OER conditions. This study enhances the performance and stability of polyoxometalates (POMs) for OER by anchoring keggin-type POM [TiCoW₁₁O₄₀]^7- nanosheets onto a conductive, carbon-protected manganese oxide (C-Mn₂O₃) nanospheres support. The acquired porous framework enhances POM/C-Mn₂O₃ (PCM) contact, improving stability, reaction kinetics, and redox activity by offering nucleation sites, electronic pathways, and abundant active sites, significantly boosting OER activity. The resulting PCM nanohybrid demonstrates remarkable OER activity in 1 M KOH, requiring only a 300 mV overpotential to achieve a current density of 10 mA cm^-2 with a Tafel slope of 88 mV/dec. The PCM electrocatalyst also shows high mass activity (784 A/g at 1.6 V) and maintains stability over 100 hours at 100 mA cm^-2 without performance fatigue. Consequently, this study offers a viable strategy for developing efficient, durable electrocatalysts using low-cost materials.