Tailoring the Spin State of CoFe PBA to Break the Activity‐Stability Trade‐off in H ₂ O ₂ Electrosynthesis

ABSTRACT Hydrogen peroxide (H 2 O 2 ) is an essential chemical whose conventional production is environmentally unsustainable, driving the pursuit of electrochemical synthesis via the two‑electron oxygen reduction reaction (2e – ORR). However, the intractable trade‐off between activity and stability hampers its industrialization, spin‐control engineering offers a compelling strategy that maintains structural integrity while enabling reversible electronic tunability. Herein, we demonstrate a CoFe Prussian blue analogue (CoFe PBA) catalyst with precisely regulated atomic coordination (Co─N─C─Fe) and spin states, enabling simultaneous high activity, selectivity, and stability in the 2e − ORR for H 2 O 2 production. This synergistic configuration pairs high‐spin Co sites, which facilitate strong O 2 adsorption, with low‐spin Fe sites that ensure structural robustness. The concerted effect of these sites effectively suppresses O─O bond cleavage, thereby guaranteeing high selectivity for H 2 O 2 generation. Consequently, CoFe PBA exhibits exceptional performance, achieving not only a high H 2 O 2 production rate of 6.74 mol g cat −1 h −1 with near‐100% initial selectivity but also outstanding operational stability, retaining 92.93% of its selectivity even after 3000 cycles in a concentrated alkaline electrolyte. Our work highlights spin‐state engineering as a viable strategy to overcome the longstanding activity, selectivity–stability trade‐off in electro‐synthesis H 2 O 2 .