Single-atom Iron Catalysts over Carbon Nanosheets with Tuned Defects for Efficient Phenol Degradation via Peroxydisulfate Activation

The large-scale application of high-performance Fe-C composites in advanced oxidation processes (AOPs) for water treatment is constrained by their complex synthesis and high cost. This study reports a low-cost Fe/N-C catalyst composed of nitrogen-doped carbon nanosheets containing abundant defects (sp3-C/sp2-C = 0.66) and single-atom iron sites.

This catalyst is prepared using coal-tar pitch (CTP), a common by-product of the coal chemical industry, as the carbon precursor, dicyandiamide as the auxiliary nitrogen source, and FeCl3·6H2O as the iron precursor, via a self-assembly and pyrolysis strategy that utilizes graphitic carbon nitride (g-C3N4) as a template. The Fe/N-C catalyst exhibits outstanding catalytic performance for the activation of peroxydisulfate (PDS), achieving over 98% phenol degradation within 30 minutes and 60% total organic carbon (TOC) removal rate.