Dual-Regulation Engineering of Spinel Co3O4 via Mo Electron Buffering and Asymmetric Sites Coupling for Acidic Oxygen Evolution Reaction

We present a synergistic strategy integrating octahedrally coordinated Mo species as electron buffer and asymmetric site coupling in spinel Co3O4 to achieve acidic oxygen evolution reaction (AOER) activity and durability. The introduced Mo species function as dynamic electron reservoirs, effectively activating and stabilizing tetrahedral Co sites while enabling synergistic electronic coupling between tetrahedral and octahedral sites. This dual-regulation mechanism successfully suppresses cobalt overoxidation and subsequent ion dissolution by maintaining optimal charge redistribution. Furthermore, the asymmetric electronic coupling induced by Mo adjacent to both tetrahedral and octahedral sites facilitates the direct coupling of *O–*O radicals, accelerating oxygen molecule formation. The optimized Mo–Co3O4 NNAs demonstrate remarkable performance metrics: a low overpotential of 310 mV at 10 mA cm–2, exceptional stability over 200 h in 0.5 M H2SO4, and minimal degradation rate (0.09 mV h–1). These achievements position it among the most competitive acid-stable non-precious-metal-based AOER catalysts reported to date. This work establishes fundamental guidelines for designing robust nonprecious electrocatalysts in acidic media and proposes fresh perspectives for implementing oxide path mechanism (OPM) paradigms in advanced AOER.