LAUSR

Abstract Electrochemical nitrate reduction to ammonia (NRA) catalyzed by Cu-based electrodes can realize green synthesis of NH3 while removing nitrate contaminant. However, there still lacks exploration for the effect of supporting matrixes on NRA performance of Cu-based catalysts. We present here the design of three kinds of supporting matrixes including Ni foams (NF), Cu foams (CF) and carbon clothes (CC) to electrochemically grow Cu catalysts and the investigations of their NRA performance. Results show that NF-supported Cu catalyst (Cu@NF) exhibits the best performance in terms of NH3 yield rate, selectivity and Faradaic efficiency. Remarkably, at −0.23 V vs. RHE, Cu@NF delivers a NH3 yield rate up to 0.252 mmol h−1 cm−2, outperforming Cu@CF (0.148 mmol h−1 cm−2) and Cu@CC (0.076 mmol h−1 cm−2). Moreover, Cu@NF well retains NH3 yield rate and selectivity after consecutive five cycles, demonstrating an excellent stability. It is found that NF as supporting matrix can induce Ni doping to Cu catalyst for Cu@NF, which is proposed to favor atomic hydrogen reduction pathway. This work not only explores the effect of supporting matrixes on NRA performance of Cu-based catalysts but also can be extended to design rational supporting matrixes for other electrocatalytic and electro-synthetic systems.