Efficient solar-driven H2O2 synthesis in-situ and sustainable activation to purify water via cascade reaction on ZnIn2S4-based heterojunction

Hydrogen peroxide (H 2 O 2 ) is a significant green oxidant for environment and new energy, especially for Fenton-like system. Onsite production and sustainable consumption of H 2 O 2 are the two critical challenges. Here, a fantastic 2D/1D hierarchical layered ZnIn 2 S 4 /TiO 2 heterojunction is reported as an efficient catalyst for in- situ H 2 O 2 production via 2-electrons oxygen reduction (ORR) process and be rapidly activated to high concentration hydroxyl radical (•OH) for water purification under visible light irradiation. The high-quality catalyst enables superior H 2 O 2 production rate of 1530.59 μmol h −1 g −1 with an external quantum efficiency of 10.39% illuminated at 400 nm, is much higher than that of reported photocatalysts. The bimetallic sulfide ZnIn 2 S 4 can effectively promote the activation of H 2 O 2 due to the unsaturation of sulfur atoms, so that the wastewater containing tetracycline (50 ppm) can be degraded by 90% only within 60 min by ZnIn 2 S 4 /TiO 2 via this cascade reaction. This work provides a novel strategy and ZnIn 2 S 4 -based catalyst for photocatalytic Fenton-like reaction.