A novel solar-driven self-Fenton reaction system with spatially separated H₂O₂ generation and activation sites for efficient degradation of refractory pollutants

Solar-driven self-Fenton reaction (SSFR), as a green and sustainable water treatment technology, has attracted widespread attention. However, the SSFR still faces challenges such as competing reaction between H₂O₂ generation and activation, formation of iron sludge and narrow pH application range. Herein, we rationally constructed a novel SSFR system with spatially separated H₂O₂ generation and activation sites based on a floatable Janus hydrophobic photocatalyst with local hydrophilic sites. This system exhibited a high rate constant for oxcarbazepine degradation across a wide pH range and in the presence of diverse anions/cations, significantly outperforming the traditional photo-Fenton system. Additionally, the SSFR system demonstrated high catalytic activity for the degradation of various refractory pollutants under continuous flow. All these improvements stem from the advantages of the obtained hydrophobic photocatalyst which can floating on water surface, thus enhancing O₂ mass transfer. Furthermore, the local hydrophilic sites can effectively decompose H₂O to supply protons continuously. Therefore, it achieved an extremely high H₂O₂ production rate (53.5 times higher than that of the dispersed system) for the following Fenton-like reaction. This work provides new insights into the rational design of highly efficient SSFR system, pushing green and sustainable water treatment technology toward a scalable and practical application. © 2025 Elsevier B.V.