Metal-organic frameworks-derived Fe3O4@NC catalyst for selective electrocatalytic reduction of nitrate to dinitrogen

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 521; p. 166825
• Main Authors: Li, Ruofan, Fan, Jianwei, Zhang, Wei-xian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2025
• Subjects: Electrocatalytic denitrification; Ferrous iron; Magnetite; Metal-organic frameworks (MOFs); N2 selectivity; Electrocatalytic denitrification; Ferrous iron; Magnetite; N2 selectivity; Metal-organic frameworks (MOFs)
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2025.166825

Electrocatalytic reduction of nitrate (NO3−-N) to benign nitrogen gas (N2) presents a new solution for sustainable environmental remediation, which requires efficient and stable catalysts. Herein, a metal-organic frameworks-derived catalyst featuring magnetite dispersed on nitrogen-doped carbon (Fe3O4@NC) is reported. Laboratory experiments show that Fe3O4@NC possess competent NO3−-N removal efficiency (63.30 %) and N2 selectivity (96.68 %), while maintaining remarkable stability over 10 consecutive cycles. The Fe(II)/Fe(III) redox cycle within Fe3O4 lattice accelerates efficient electron transfer and enables the dynamic regeneration of active sites. Density functional theory (DFT) calculations further demonstrates that the incorporation of a carbon shell and further N doping facilitates NO3− adsorption, resulting in a more stable adsorption configuration, and lowered the reaction energy barrier of the rate-determining step, leading to a higher reactivity. This work formulates a low-cost noble-metal-free catalyst for nitrate removal and offers insights into rational design of mixed-valence oxides for advanced environmental remediation technologies. [Display omitted] •The Fe3O4@NC catalyst was synthesized with NH2-MIL-88B(Fe) with the precursor.•Fe3O4@NC exhibited superior NO3−-N removal efficiency (63.30 %), N2 selectivity (96.68 %), and stability (10 times).•The incorporated N-doped carbon shell contributed to the enhanced catalytic activity.•The inherent Fe(II)/Fe(III) redox cycle within Fe3O4 promoted electron transfer and enabled active site regeneration.