Ultrahigh Peroxymonosulfate Utilization Over a Single-Atom Iron-N-C Catalyst for Efficient Fenton-Like Chemistry via...

Area of Science:

• Environmental Chemistry
• Catalysis
• Materials Science

Background:

• Single-atom catalysts (SACs) are crucial for peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs).
• Understanding the electronic structure's role in SAC activity is limited, with focus often on thermodynamics.
• Graphitic carbon nitride (g-C3N4) is a common support for SACs in water treatment.

Purpose of the Study:

• To develop and investigate transition metal single-atom catalysts (M-N4 moieties) supported on g-C3N4 (MSA CN) for PMS activation.
• To evaluate the catalytic performance of Fe, Co, and Cu SACs for 4-chlorophenol degradation.
• To elucidate the electronic structure-activity relationship governing PMS activation and pollutant degradation.

Main Methods:

• Synthesis of single-atom M-N4 moieties (M = Fe, Co, Cu) on graphitic carbon nitride (MSA CN).
• Evaluation of catalytic activity for 4-chlorophenol degradation using PMS.
• Density Functional Theory (DFT) calculations to investigate electronic structure and reaction mechanisms.

Main Results:

• FeSA CN demonstrated superior catalytic activity, achieving a rate constant 2-551 times higher than reported systems.
• High degradation efficiency (≈100%) was observed at ultralow catalyst (0.06 mg L⁻¹) and PMS (0.2 mM) concentrations.
• DFT revealed that Fe-N-C spin polarization enhances d-orbital overlap with PMS, promoting electron transport and oxidation capacity.

Conclusions:

• FeSA CN exhibits exceptional efficiency in PMS-based AOPs for degrading 4-chlorophenol via non-radical pathways.
• The study highlights the critical role of electronic structure, specifically spin polarization, in SAC performance.
• This work provides a mechanistic basis for designing advanced Fe-SAC/PMS systems for water remediation.