Multisite Atomic‐Oxygen‐Passivation Iodide Vacancies Stabilize Perovskite Interfaces for Efficient Solar H ₂ O ₂ and Imines Production

The intrinsic instability and defect‐mediated performance degradation of lead halide perovskite quantum dots (PQDs) fundamentally limit their photocatalytic applications. Here, we report a materials design strategy that leverages sulfonic acid‐functionalized covalent organic frameworks (COF‐SO 3 ) with flexible alkyl tethers to achieve multisite atomic‐oxygen passivation of encapsulated CsPbI 3 QDs. This unique architecture enables strong O−Pb coordination between the spatially ordered ‐SO 3 − groups and undercoordinated Pb 2+ sites on the CsPbI 3 QDs, which effectively passivates iodide vacancies (V I ) and enhances structural stability. The confined growth within the COF mesopores simultaneously creates an S‐scheme heterojunction. Interfacial electron redistribution establishes an internal electric field that drives directional charge separation while preserving the high redox potentials of both components. This synergistic system achieves a remarkable H 2 O 2 production rate of 79.09 mmol·g − 1 ·h − 1 under visible light, with an apparent quantum yield of 13.54% at 420 nm and a solar‐to‐chemical efficiency of 1.17%, concurrently facilitating the selective oxidation of benzylamine to bis‐benzylidene diamine (>99% selectivity). Mechanism studies reveal that the flexible ‐SO 3 − /Pb 2+ coordination enhances the V I formation energy and the CsPbI 3 (100) facet drives oxygen reduction via a low‐energy •O 2 − pathway. This work provides a generalizable platform for stabilizing sensitive semiconductor materials and designing efficient dual‐functional photocatalysts.