Multi‐Energy‐State Covalent Organic Framework/Sulfur‐Vacancy‐Engineered Mn _0.2 Cd _0.8 S S‐Scheme Photocatalyst for Enhanced Light Harvesting and H ₂ O ₂ Generation

Abstract

ABSTRACT Hydrogen peroxide (H 2 O 2 ) is an essential green oxidant with broad industrial relevance. Photocatalytic oxygen reduction reaction (ORR) offers a sustainable method for producing oxygen, yet its efficiency is limited by poor charge separation and severe carrier recombination. Single‐component photocatalysts suffer from sluggish carrier dynamics, while multi‐energy‐state systems frequently experience recombination at intermediate states. S‐scheme heterojunction engineering offers an effective strategy to address these challenges by regulating interfacial charge transfer while preserving strong redox potentials. Here, we report the construction of an S‐scheme photocatalyst by integrating a triazine‐based covalent organic framework (COF) with sulfur‐vacancy‐rich Mn 0.2 Cd 0.8 S (Sv‐MCS). This dual‐functional design preserves both the intrinsic n→π* electronic transitions of the COF and defect‐state absorption of Sv‐MCS, delivering an exceptional H 2 O 2 production rate of 5389.6 µmol·h −1 ·g −1 in pure water. Concurrently, the photostability of the catalyst is simultaneously enhanced. X‐ray absorption fine‐structural analysis confirms interfacial Cd–O coordination between Cd atoms and COF carbonyl groups. In situ spectroscopies combined with density functional theory elucidate a preferential two‐electron ORR pathway, while femtosecond transient absorption spectroscopy confirms suppressed carrier recombination enabled by synergistic S‐scheme charge transfer and interfacial chemical bonding. This work establishes design principles for multi‐energy‐state S‐scheme photocatalysts and advances solar‐driven H 2 O 2 production toward artificial photosynthesis.