Boosting Electrochemical Nitrate Reduction at Low Concentrations Through Simultaneous Electronic States Regulation and Proton Provision
Wenlin Zhang, Yuzhuo Zhou, Yong Zhu, Yabo Guo, Bo Zhang, Lu‐Hua Zhang, Fei Li, Fengshou Yu
Abstract
Abstract Electrochemically converting nitrate (NO 3 − ) into ammonia (NH 3 ) has emerged as an alternative strategy for NH 3 production and effluent treatment. Nevertheless, the electroreduction of dilute NO 3 − is still challenging due to the competitive adsorption between various aqueous species and NO 3 − , and unfavorable water dissociation providing * H. Herein, a new tandem strategy is proposed to boost the electrochemical nitrate reduction reaction (NO 3 RR) performance of Cu nanoparticles supported on single Fe atoms dispersed N‐doped carbon (Cu@Fe 1 ‐NC) at dilute NO 3 − concentrations (≤100 ppm NO 3 − ‐N). The optimized Cu@Fe 1 ‐NC presents a FE NH3 of 97.7% at −0.4 V versus RHE, and a significant NH 3 yield of 1953.9 mmol h −1 g Cu −1 at 100 ppm NO 3 − ‐N, a record‐high activity for dilute NO 3 RR. The metal/carbon heterojunctions in Cu@Fe 1 ‐NC enable a spontaneous electron transfer from Cu to carbon substrate, resulting in electron‐deficient Cu. As a result, the electron‐deficient Cu facilitates the adsorption of NO 3 − compared with the pristine Cu. The adjacent atomic Fe sites efficiently promote water dissociation, providing abundant * H for the hydrogenation of * NO x e at Cu sites. The synergistic effects between Cu and single Fe atom sites simultaneously decrease the energy barrier for NO 3 − adsorption and hydrogenation, thereby enhancing the overall activity of NO 3 − reduction.