Hydroxyl Defects‐Mediated Hydrolytic Activation of Peroxydisulfate Under Nanoconfinement: Role of Lewis Basic Sites for Altering the Photosensitized Species and Pathways

Abstract Herein, the pivotal mechanism of defect engineering‐mediated triazine‐based conjugated polymers (TCPs) is comprehensively elucidated for photosensitized activation of peroxydisulfate (PDS) under nanoconfinement by encapsulating the defective polymer framework into the nanochannel of SBA‐15 (d‐TCPs@SBA‐15). The incorporated hydroxyl defects (‐OH defects) substantially accelerate the accumulation of electrons at ‐OH defects, forming the Lewis basic sites. Due to the facilitated elongation of the S─O bond and reduced energy barrier of SO ₅ * generation, the captured PDS undergo prehydrolysis process, oxidized into O ₂ ⁻ and ¹ O ₂ by surrounding h ⁺ , thereby setting apart from the conventional reductive activation of SO ₄ ⁻ /•OH generation occurred in pristine TCPs (p‐TCPs). Crucially, this work represents a pioneering effort in exploring the PDS activation pathway upon the defective polymer under the nanoconfinement to leverage kinetic merits of slow photon effect and reactive oxygen species (ROSs) enrichment, and the novel prehydrolysis activation mechanism involved may catalyze the rational design of photocatalysts featuring Lewis‐acid/base centers.