Boosted H₂O₂ utilization and selective hydroxyl radical generation for water decontamination: Synergistic roles of...

H₂O₂ as a green oxidant plays a crucial role in numerous green chemical reactions. However, how to improve its activation and utilization efficiency as well as regulate the distribution of ROS remains a pressing challenge. In this work, a sulfur quantum dots (SQDs) modified zero-valent iron (SQDs@ZVI) was delicately designed and prepared, whose iron sites can coordinate with strongly electronegative sulfur atoms to construct highly reactive Fe-S dual active sites, for high-efficient selective H₂O₂ activation and utilization with potent ^•OH production. Experimental tests, in situ FTIR/Raman spectra and theoretical calculations demonstrated that SQDs modulates the local coordination structure and electronic density of iron centers, thus effectively enhancing its Fenton reactivity and promoting the rate-limiting H₂O₂ adsorption and subsequent barrierless dissociation of peroxyl bonds into ^•OH via the formation of bridged S-O-O-Fe complexes. Consequently, substantial generated surface-bound ^•OH induced by the highly reactive Fe-S dual sites enabled excellent degradation of miscellaneous organic pollutants over a broad pH range (3.0-9.0). The developed device-scale Fenton filter realized durable performance (up to 200 h), verifying the vast potential of SQDs@ZVI with diatomic sites for practical application. This work presents a promising strategy to construct metal-nonmetal diatomic active sites toward boosting selective activation and effective utilization of H₂O₂, which may inspire the design of efficient heterogeneous Fenton reaction for water decontamination.