Electrocatalytic Reduction of Nitrate to Nitrogen on Free-Standing Fe–C₃N₄/Carbon Nanostructured Film Catalysts with High Activity and Stability

Electrochemical nitrate (NO3–) reduction reaction (NO3RR) is an attractive technique for regulating the nitrogen cycle. Nevertheless, the drastic changes in electrocatalytic activity across a broad range of nitrate concentrations and solution pH values, as well as the poor stability of catalysts, have seriously affected the practical application prospects of iron-based catalysts. In this study, a self-standing iron–carbon nitride/carbon nanostructured film (Fe–C3N4/CF) catalyst is synthesized by the in situ growth of NH2–Fe-MOF nanoparticles on cotton fabric (CTF) substrate, followed by subsequent pyrolysis. Benefiting from the hierarchical mass transport engineering, Fe–N coordination, and electron redistribution engineering, the resultant catalyst addresses the aforementioned issues well. The resultant catalyst exhibits exceptional performance in the electrocatalytic reduction of nitrate to N2. It features a high nitrate conversion rate of over 95.3%, excellent N2 selectivity of over 97.0%, outstanding stability for up to 30 cycles, and broad applicability under diverse conditions. These findings offer a promising solution to the bottleneck issues associated with iron-based catalysts for electrocatalytic denitrification.