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-COOFeIII) wherein CDCOOFeIII active center activates H2O2 to produce hydroxyl radicals (center dot OH) reaching 105 times larger than that of the Fe3+/H2O2 system. The key is the center dot 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-COOFeIII via hydrogen bonds, promoting the electron-transfer rate constants during the redox reaction of CD defects. The antibiotics removal efficiency in the CD-COOFeIII/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.

Automated summary

In this study, a novel carbon dot catalyst CD-COOFeIII was developed, which can efficiently generate hydroxyl radicals with an activity 105 times higher than the Fe3+/H2O2 system. Real-time infrared spectroscopy and kinetic isotope effects measurement revealed the importance of high electron-transfer rate constants of CD defects and their self-regulated proton-transfer behavior. The CD-COOFeIII/H2O2 system showed at least 51 times higher efficiency in antibiotics removal compared to the Fe3+/H2O2 system under equivalent conditions.