Highly Efficient Electrochemical Nitrate and Nitrogen Reduction to Ammonia under Ambient Conditions on Electrodeposited Cu‐Nanosphere Electrode

Abstract

AbstractThe electrochemical reduction reaction of nitrogenous species such as NO3− (NO3RR) and N2 (NRR) is a promising strategy for producing ammonia under ambient conditions. However, low activity and poor selectivity of both NO3RR and NRR remain the biggest problem of all current electrocatalysts. In this work, we fabricated Cu‐nanosphere film with a high surface area and dominant with a Cu(200) facet by simple electrodeposition method. The Cu‐nanosphere film exhibits high electrocatalytic activity for NO3RR and NRR to ammonia under ambient conditions. In the nitrate environment, the Cu‐nanosphere electrode reduced NO3− to yield NH3 at a rate of 5.2 mg/h cm2, with a Faradaic efficiency of 85 % at −1.3 V. In the N2‐saturated environment, the Cu‐nanosphere electrode reduced N2 to yield NH3 with the highest yield rate of 16.2 μg/h cm2 at −0.5 V, and the highest NH3 Faradaic efficiency of 41.6 % at −0.4 V. Furthermore, the Cu‐nanosphere exhibits excellent stability with the NH3 yield rate, and the Faradaic efficiency remains stable after 10 consecutive cycles. Such high levels of NH3 yield, selectivity, and stability at low applied potential are among the best values currently reported in the literature.