Single‐Atom Cocatalyst‐Loaded Semiconductors for Photo‐Fenton‐Like Wastewater Treatment

Solar‐driven photo‐Fenton reaction offers a sustainable solution to wastewater treatment by using photogenerated hydroxyl radicals ( • OH) to oxidize organic/inorganic contaminants (dyes, pigments, antibiotics, drugs, phenol derivatives, etc.) to nontoxic chemicals. The oxidation potential of • OH ( E 0 = 1.9–2.7 V vs. NHE) is high enough to completely oxidize most of the organic contaminants to CO 2 . For an effective photo‐Fenton process, the choice of an appropriate photocatalyst system with a suitable bandgap and band positions is crucial. Further, the loading of a cocatalyst can substantially improve the charge transfer dynamics, thus reducing the electron‐hole recombination and providing active sites for substrate adsorption for the photocatalytic process. Recently, atomic site cocatalysts have been integrated into semiconductors to attain an improved atom economy, high surface‐active sites, and hence an improved photo‐Fenton activity. In this review, we have described the recent progress and utilization of single‐atom cocatalyst (SAC)‐loaded photocatalysts for photo‐Fenton reactions, their structural features, synthetic strategies, and applications to water treatment. The advantages of photo‐Fenton reactions with SAC‐loaded photocatalysts over the conventional water treatment processes, which often face difficulty in treating low pollutant concentrations, have been described in detail.