Modulating the Active Hydrogen Adsorption on Fe-N Interface for Boosted Electrocatalytic Nitrate Reduction with Ultra-long Stability.

The electrocatalytic reduction of nitrates to nitrogen is an environmentally friendly approach for efficient N-cycle management (towards a nitrogen-neutral cycle). However, poor catalyst durability and the competitive hydrogen evolution reaction significantly impede its practical application. Interface-chemistry engineering, utilizing the close relationship between the catalyst surface/interface microenvironment and electron/proton transfer process, has facilitated the development of catalysts with high intrinsic activity and physicochemical durability. This study reports the synthesis of a nitrogen-doped carbon-coated rice-like iron nitride (RL-Fe 2 N@NC) electrocatalyst with excellent electrocatalytic nitrate-reduction reaction (NO 3 RR) activity (high N 2 selectivity (∼96%) and NO 3 - conversion (∼86%)). According to detailed mechanistic investigations by in-situ tests and theoretical calculations, the strong hydrogenation ability of iron nitride and enhanced nitrate enrichment of the system synergistically contributed to the rapid hydrogenation of nitrogen-containing species, increasing the intrinsic activity of the catalyst and reducing the occurrence of the competing hydrogen-evolution side reaction. Moreover, RL-Fe 2 N@NC showed excellent stability, retaining good NO 3 - -to-N 2 electrocatalysis activity for more than 40 cycles (one cycle per day). This paper could guide the interfacial design of Fe-based composite nanostructures for electrocatalytic nitrate reduction, facilitating a shift towards nitrogen neutrality. This article is protected by copyright. All rights reserved.