Zinc-mediated activator crafting of single-atomic Mn–N2|Zn–N6 sites and nanoclusters within microporous carbon networks for efficient oxygen reduction

Abstract

Metal-organic frameworks (MOFs) serve as superior precursors for porous carbon electrocatalysts due to tailorable coordination environments and structural adaptability. However, pyrolysis-induced structural degradation causes metallic aggregation and pore disorder, severely impairing oxygen reduction reaction (ORR) kinetics. We develop a confined ZnCl₂ etching strategy to convert metal triazolate frameworks into microporous-dominated ZnMn–N–C catalysts, exposing active sites at triple-phase interfaces. Molten ZnCl₂ simultaneously engineers microporores and suppresses metal coalescence, yielding atomically dispersed Mn–N₂|Zn–N₆ moieties. The optimized catalyst achieves a 0.867 V half-wave potential (vs. RHE) in an alkaline media. In zinc-air batteries, it delivers 889 mWh g⁻¹_Zn at 50 mA cm⁻² with 49 mV day over 150 h, while maintaining a <0.87 V charge-discharge gap at 10 mA cm⁻² for over 100 h. This work provides a rational strategy for spatially optimizing active sites via confined chemical etching, demonstrating significant potential for developing durable zinc-air batteries with enhanced reaction kinetics.