Homogeneous Carbon Dot-Anchored Fe(III) Catalysts with Self-Regulated Proton Transfer for Recyclable Fenton Chemistry

Fenton chemistry has been widely studied in a broad range from geochemistry, chemical oxidation to tumor chemodynamic therapy. It was well established that Fe³⁺/H₂O₂ resulted in a sluggish initial rate or even inactivity. Herein, we report the homogeneous carbon dot-anchored Fe(III) catalysts (CD-COOFe^III) wherein CD-COOFe^III active center activates H₂O₂ to produce hydroxyl radicals (^•OH) reaching 105 times larger than that of the Fe³⁺/H₂O₂ system. The key is the ^•OH flux produced from the O–O bond reductive cleavage boosting by the high electron-transfer rate constants of CD defects and its self-regulated proton-transfer behavior probed by operando ATR-FTIR spectroscopy in D₂O and kinetic isotope effects, respectively. Organic molecules interact with CD-COOFe^III via hydrogen bonds, promoting the electron-transfer rate constants during the redox reaction of CD defects. The antibiotics removal efficiency in the CD-COOFe^III/H₂O₂ system is at least 51 times large than the Fe³⁺/H₂O₂ system under equivalent conditions. Our findings provide a new pathway for traditional Fenton chemistry.