Heterostructured Co-Doped-Cu2O/Cu Synergistically Promotes Water Dissociation for Improved Electrochemical Nitrate Reduction to Ammonia

Abstract

Electrochemical nitrate reduction reaction (NO₃RR) has recently emerged as a promising approach for sustainable ammonia synthesis and wastewater treatment, while the activity and selectivity for ammonia production have remained low. Herein, rational design and controllable synthesis of heterostructured Co-doped Cu₂O/Cu nanoparticles embedded in carbon framework (Co-Cu₂O/Cu@C) is reported for NO₃RR. The Co-Cu₂O/Cu@C exhibits a high ammonia yield rate of 37.86 mg h^-1 mg^-1 _cat. with 98.1% Faraday efficiency, which is higher than those obtained for most of the Cu-based catalysts under similar conditions. Density functional theory calculations indicated that the strong electronic interactions at Cu/Co-Cu₂O interface facilitate the N species deoxygenation process and doping of Co promotes water dissociation to generate ^*H for the N species hydrogenation process, leading to enhanced NO₃RR performance. This work provides a new design strategy toward high-performance catalysts toward NO₃RR for ammonia generation.

Keywords: 15N isotope labeling; ammonia synthesis; heterostructures; nitrate reduction reaction.