Efficient degradation of organic pollutants without any external assistance over a wide pH range using carbon vacancy-modified Fe–N–C catalysts†

Currently, water treatment usually requires additional light illumination or oxidants for the degradation of organic pollutants, which increases the costs and is not conducive to practical application. In this study, carbon vacancy-modified Fe–N–C single-atom catalysts (Cv-Fe–N–C SACs) were prepared through one simple acid-etching and pyrolysis process. Interestingly, we found that Cv-Fe–N–C SACs could degrade organic pollutants without any external assistance (such as oxidants or light illumination). The Cv-Fe–N–C SACs could remove over 99% of Rhodamine B (RhB) within 10 min at room temperature. The degradation of organic pollutants with the Cv-Fe–N–C SACs was attributed to their ability to activate dissolved oxygen for producing superoxide (O₂˙⁻). In addition, the catalysts showed high activity over a broad pH range (3–11) and held rather good stability after 5 recycles. This study proved that the Cv-Fe–N–C SACs are highly efficient catalysts for degrading organic pollutants. These catalysts have the potential to make sewage treatment more efficient and less expensive.