Intrinsic structure-function connections of carbon-encapsulated nanoscale zero-valent-iron using various pyrolysis...

Carbon-encapsulated nanoscale zero-valent-iron (C@Fe⁰) derived from plant-based extracts has been the subject of growing interest due to its environmental friendliness. However, the effects of various pyrolysis atmospheres on the structure-function connections of C@Fe⁰ are still unclear. In this study, three pyrolytic atmospheres, namely Air, N₂, and 5% H₂/Ar were selected to fabricate X-C@Fe⁰ (X represented as A, N, H) for removing 2,4,6-Trichlorophenol (TCP), and the relationships between their structures and functions were demonstrated. The N-C@Fe⁰ with improved hydrophobicity exhibited superior TCP adsorptive performance compared to H-C@Fe⁰ and A-C@Fe⁰. Apart from this, N-C@Fe⁰ effectively reduced TCP through dechlorination, this process achieved 25.9% dichlorination efficiency, and in turn alleviated products toxicity. Electrochemical tests and density functional theory calculations showed that the substitution of nitrogen with carbon in N-C@Fe⁰ elevated the Fe-d band center and enhanced the hybridization between Fe-3d and C-2p orbital, which collectively promoted the dichlorination of TCP. This study will provide practical guideline for improving the intrinsic activity of iron-carbon materials using pyrolytic atmosphere engineering.