Boron-Tuned Covalency Enables Durable and High-Performance Perovskite OER Catalysts

Perovskite catalysts show great promise for the oxygen evolution reaction (OER) but still face challenges in activity and stability. Here, we report boron incorporation into Sr 2 (FeCo 0.6 Mo 0.4 )O 5+δ to tailor the Co–O–Fe covalency and electronic states, delivering 300 mV at 10 mA cm − 2 and a 67 mV dec − 1 Tafel slope with > 140 h durability in 1 m KOH. Spectroscopy shows lowered Co/Fe valences and an increased fraction of lattice oxygen, while Density Functional Theory(DFT) (ELF/DOS/free-energy) indicates strengthened Transition Metal-Oxygen (TM─O) bonding and reduced reaction barriers. These findings support a shift toward an adsorbate evolution like pathway with suppressed lattice oxygen participation, rationalizing both the enhanced activity and robustness. Flexible Zn air batteries using Sr 2 (FeCo 0.6 Mo 0.4 ) 0.9 B 0.1 O 5+δ exhibit lower charging overpotentials and superior cycling stability than Pt/C+RuO 2 , highlighting device relevance. This work establishes metalloid doping enabled covalency engineering as a general strategy to boost OER performance and stability in perovskites.