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

Abstract

Hydrogen peroxide (H2O2) is a significant green oxidant for environment and new energy, especially for Fenton-like system. Onsite production and sustainable consumption of H2O2 are the two critical challenges. Here, a fantastic 2D/1D hierarchical layered ZnIn2S4/TiO2 heterojunction is reported as an efficient catalyst for in-situ H2O2 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 H2O2 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 ZnIn2S4 can effectively promote the activation of H2O2 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 ZnIn2S4/TiO2via this cascade reaction. This work provides a novel strategy and ZnIn2S4-based catalyst for photocatalytic Fenton-like reaction.