Boosting Nitrate to Ammonia via the Optimization of Key Intermediate Processes by Low-Coordinated Cu–Cu Sites

Abstract

The electrochemical reduction of nitrate to ammonia (NO3RR) has emerged as a promising but challenging orientation in sustainable development. Cu is one of the most effective NO3RR catalysts. However, the accumulation of NO2− on their surface has erected bars to the further improvement of NO3RR efficiency. Herein, Cu-based electrocatalyst with low-coordinated Cu atoms (Cu-LC) is synthesized via the instantaneous ablation and rapid cooling of the Cu target by pulse laser and proposed as a new NO3RR electrocatalyst, which exhibits enhanced NO3RR activity with NH3 selectivity of 97.01%, yield rate of 0.624 mmol h−1 cm−2 at −0.8 V versus RHE and long-term durability, superior to most reported Cu-based catalysts. The introduction of low-coordinated Cu sites upshifts the Cu d-band center to near the Fermi Level, enhancing the adsorption of key intermediates (*NO2, *NO) in NO3RR, and also effectively regulating the generation of *NO2 and hydrogenation process, inhibiting the accumulation of NO2− on the Cu-LC surface, thus achieving efficient NH3 production. Furthermore, when evaluated as cathode material in Zn–NO3− battery, an open circuit voltage of 1.3 V and a power density of 3.1 mW cm−2 are achieved by the Cu-LC-based battery, highlighting a promising multifunctional system for ammonia production and energy supply.