Light-induced H₂O₂ self-supply enables FeII/FeIII cycle in MIL-100(Fe)/Zn₃in₂S₆ heterojunction for dark-light dual...

Reactive oxygen species (ROS)-mediated sterilization typically relies on continuous light irradiation or exogenous H₂O₂ addition, limiting their practical utility under dark or resource-limited conditions. Herein, we rationally design an S-scheme MIL-100(Fe)/Zn₃In₂S₆ heterojunction (M₅Z₁-1@ZIS2) by in-situ growing Zn-doped MIL-100(Fe) on Zn₃In₂S₆, achieving synergistic light-harvesting and ROS self-supply capabilities. The incorporation of Zn₃In₂S₆ enhances electron density around Fe²⁺ sites while modulating Fe³⁺ states, significantly improving O₂ activation and H₂O₂ affinity. This unique electronic regulation enables the heterojunction to generate superoxide radical(·O₂^-)-dominated ROS even in the dark. Notably, visible-light pretreatment induces active In sites in Zn₃In₂S₆ to produce H₂O₂, which accumulates and sustains the FeII/FeIII redox cycle in the absence of light, driving continuous hydroxyl radical(·OH)-dominated ROS generation. Combined characterizations including X-ray photoelectron spectroscopy (XPS) and Electron Paramagnetic Resonance (EPR) confirm H₂O₂-mediated Fe²⁺ regeneration and ROS persistence. The M₅Z₁-1@ZIS2 heterojunction exhibits exceptional antibacterial performance, achieving ≥99.9% inactivation of Escherichia coli (E. coli) within 1.5 h in the dark and 40 min under visible light. This work provides a strategy for designing self-sustaining catalytic systems that leverage light-driven H₂O₂ supply to enable day-night ROS functionality. Furthermore, M₅Z₁-1@ZIS2 loaded on polyvinylidene fluoride (PVDF) film can achieve an efficiency of over 99% for particulate matter (PM) pollutants at the wind speeds of 1.5 m/s and 0.5 m/s and reach a maximum adsorption efficiency of 99.5% for formaldehyde within 19 min, highlighting its potential for all-weather air purification via ROS-mediated environmental remediation.