Interface engineering cerium-doped copper nanocrystal for efficient electrochemical nitrate-to-ammonia production

Developing low-cost and high-performance electrocatalysts for electrochemical nitrate reduction to ammonia (NRA) is of great importance to alleviate increasingly energy demand and environmental pollution. Cu electrodes have been widely explored towards NRA, while high overpotential is always required and ammonia selectivity is relatively low. Herein, Ce-doping Cu electrode is designed and fabricated via electrochemical deposition strategy and its electrocatalytic NRA in alkaline conditions is investigated. Effect of the Ce content on the performance of the Ce-doped Cu electrodes are studied, showing that the Cu10Ce10 demonstrates the best performance. It achieves a high ammonia yield rate of 0.99 mmol h−1 cm−2, Faradaic efficiency of 98.43%, nitrate conversion rate of 94% and NH3 selectivity of 79.33%. It is found that Ce-doping Cu electrode could tune electronic structure of Cu by generating Cu/Cu2O interfacial structure as active phase, which reduces the overpotential of nitrate reduction and improves the NH3 selectivity of Cu electrodes.