Modulating electron density enable efficient cascade conversion from peroxymonosulfate to superoxide radical driven...

Area of Science:

• Environmental Chemistry
• Catalysis
• Materials Science

Background:

• Peroxymonosulfate (PMS)-based photo-Fenton-like reactions are effective for water decontamination.
• Generating superoxide radicals (•O₂^-) for these reactions remains a challenge.
• Targeted construction of •O₂^--mediated systems is crucial for enhanced selectivity.

Purpose of the Study:

• To develop an electron-rich/-poor dual sites driven •O₂^--mediated cascade photo-Fenton-like system.
• To modulate electron density for preferential PMS adsorption and activation.
• To achieve highly selective water decontamination with improved efficiency.

Main Methods:

• Development of a dual-site catalyst with modulated electron density.
• Experimental investigation of PMS adsorption and activation pathways.
• Theoretical calculations to understand reaction mechanisms.
• Testing the system's efficiency in removing various contaminants and its resistance to interfering substances.

Main Results:

• PMS preferentially adsorbs on electron-poor Co sites, promoting O-O bond cleavage to form H₂O₂.
• Generated H₂O₂ migrates to electron-rich O sites for O-H bond cleavage, generating •O₂^-.
• The system selectively eliminates contaminants with low K_OW and pKa values.
• The system demonstrates remarkable resistance to inorganic ions, humic acid, and real water matrices.

Conclusions:

• A novel cascade photo-Fenton-like system utilizing electron-rich/-poor dual sites was successfully developed.
• The system efficiently and selectively generates •O₂^- for water decontamination.
• This strategy offers a plausible approach for accurate and efficient •O₂^- generation in environmental remediation.