Biomimetic Dual-Iron-Site Single-Atom Nanozymes for N 2 -Selective Electrocatalytic Denitrification

Electrocatalytic denitrification (ECDN) for the reduction of NO to N offers an effective and environmentally benign method for removing nitrogen from wastewater, but challenges remain for poor N selectivity. To address this issue, this study reports a dual-iron-site single-atom nanozyme (SAN, FePc@F...

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Bibliographic Details
Published in:Environmental science & technology Vol. 59; no. 31; p. 16775
Main Authors: Song, Wanchao, Liu, Guoshuai, Zou, Hua, Yao, Yuan, You, Shijie
Format: Journal Article
Language:English
Published: United States 12.08.2025
Subjects:
Biomimetics
Catalysis
Denitrification
Iron - chemistry
Nitrogen
Wastewater
electrocatalytic denitrification
single-atom nanozyme
N2 selectivity
N−N coupling
ISSN:1520-5851
Online Access:Get more information
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Summary:Electrocatalytic denitrification (ECDN) for the reduction of NO to N offers an effective and environmentally benign method for removing nitrogen from wastewater, but challenges remain for poor N selectivity. To address this issue, this study reports a dual-iron-site single-atom nanozyme (SAN, FePc@FeNOC) electrocatalyst, resembling the natural cytochrome c-dependent nitric oxide reductase (cNOR). The FePc@FeNOC electrocatalyst exhibits a NO removal efficiency as high as 96.1%, accounting for N selectivity of 93.3% and Faradaic efficiency of 82.8% at a reaction time of 10 h. The theoretical results reveal that the potential-determining step of ECDN to N is more thermodynamically favorable than that to NH by FePc@FeNOC, as indicated by the lower free energy barrier for *NO to *N O (0.82 eV) compared with that for *NO to *NOH (0.87 eV). The *N O intermediate demonstrates enhanced charge separation compared with *NOH. The charge redistribution strengthens the electrostatic coupling between FePc@FeNOC and *N O , which not only stabilizes the intermediate structure but also creates a thermodynamic driving force for N formation. We further demonstrate that the superior N -selectivity (90%) of FePc@FeNOC can offer a promising electrocatalyst for removing nitrogen from realistic photovoltaic wastewater with a low energy consumption of 9.8 kWh kgN . This work provides a proof-in-concept demonstration of mimicking cNOR toward the sustainable treatment of nitrate-contaminated wastewater.
ISSN:1520-5851
DOI:10.1021/acs.est.5c04948