Synergistic reduction of iron single-atom and clusters enhances chloramphenicol degradation: Implications of surface...

Previous studies have shown that the traditional copyrolysis method for the preparation of carbon-based Fe⁰ composite materials leads to a significant increase in the surface free energy of the metal, which inevitably leads to the coexistence of iron atoms and iron clusters, and thus affects the reduction and degradation performance of pollutants. In this study, we prepared a carbon-embedded reducing agent material, referred to as NC/Fe, which incorporates both iron atoms and iron clusters. This composite effectively mitigates the pollution caused by chloramphenicol (CAP) antibiotics, which are prevalent contaminants in wastewater that pose a serious threat to global freshwater resources. The maximum degradation efficiency of CAP achieved by NC/Fe reached 98.05 % within 20 minutes, whereas the maximum dechlorination efficiency attained was 70.19 % within 8 hours. Compared with the NC/Fe material, NC/Fe-SAC-comprising only iron atoms-exhibited slightly reduced performance regarding CAP degradation; notably, the existence of iron clusters did not further influence the activity of these iron atoms. Additionally, H* is formed by the electron transfer of the encapsulated Fe⁰, and H* is then briefly adsorbed by the shell of the packaging material, thereby inhibiting the hydrogen evolution reaction. This study elucidates the reduction mechanism associated with Fe⁰ composite materials and offers novel insights into their application for environmental remediation efforts.