Dynamic Photoexcited Oxygen Vacancies beyond Static Defects Achieve 1.66 V Zn‐Air Battery

Abstract

ABSTRACT Oxygen vacancies are widely introduced into electrocatalysts to boost the oxygen reduction reaction (ORR) in Zn‐air batteries, yet their dynamic behavior under operando illumination remains largely unexplored. Herein, we demonstrate that initial synthetic oxygen vacancies (IS‐OVs) in CuO catalyst are not the final active sites, but rather precursors that in situ form highly reactive photoexcited oxygen vacancies (PE‐OVs) under illumination. Combined in situ electron paramagnetic resonance spectroscopy and calculations confirm that PE‐OVs serve as genuine active sites for the ORR, distinguishing this work from previous misassignment to IS‐OVs. The evolution originates from weakened Cu─O bonds at IS‐OV sites under illumination, promoting PE‐OVs with a more favorable electronic configuration for O 2 activation. PE‐OVs alter the ORR pathway through directional single‐electron transfer from the Cu 3d d z orbital to the O 2 π* 2px orbital, lowering the *OH dissociation barrier and enabling ultrafast O 2 ‐to‐OH − conversion. Therefore, the CuO‐OV catalyst achieves an onset potential of 1.31 V, exceeding Pt/C by ∼380 mV and the O 2 /H 2 O equilibrium by 80 mV. The assembled photo‐assisted Zn‐air battery delivers a high discharge voltage of 1.66 V with stable operation over 600 h, outperforming most reported non‐precious‐metal ORR catalysts. This manuscript presents a paradigm shift from static to dynamic defect engineering in photoelectrocatalysis.