Heterostructured Co-Doped-Cu 2 O/Cu Synergistically Promotes Water Dissociation for Improved Electrochemical Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction reaction (NO 3 RR) 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 Cu 2 O/Cu nanoparticles embedded in carbon framework (Co-Cu 2 O/Cu@C) is reported for NO 3 RR. The Co-Cu 2 O/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-Cu 2 O 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 NO 3 RR performance. This work provides a new design strategy toward high-performance catalysts toward NO 3 RR for ammonia generation.