Direct Conversion of Passivated Photo‐Corroded Sites into Active Co‐Catalysts via In Situ Targeting

Abstract Localized accumulation of carriers frequently induces corrosion on the surfaces of photocatalysts, restricting the efficacy of photocatalytic technology. The development of a strategy that precisely targets and transforms passivated corrosion regions into reactive sites holds significant potential, yet remains technically challenging. Herein, an advanced microscopy study reveals that BiOBr photocatalysts are susceptible to severe photo‐corrosion, leading to a continual thickening of Bi 2 O 3 crystalline films as the photo‐oxidation products accumulate on the photocatalytic surfaces. Through a metal cation intercalation process, it is demonstrated that the passivated Bi 2 O 3 films are precisely targeted by the accumulated holes and in situ converted to M x Bi y O z (M = Co, Mn, Fe, Pb) nanobeads that act as co‐catalysts to expedite charge transfer and enhance photostability. This work deepens the understanding of the atomistic photocorrosion mechanism of BiOBr photocatalysts and contributes to a versatile surface‐targeted photochemical modification approach to tackle widespread photocorrosion challenges.