Effect of supporting matrixes on performance of copper catalysts in electrochemical nitrate reduction to ammonia

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 ([email protected]) exhibits the best performance in terms of NH3 yield rate, selectivity and Faradaic efficiency. Remarkably, at −0.23 V vs. RHE, [email protected] delivers a NH3 yield rate up to 0.252 mmol h−1 cm−2, outperforming [email protected] (0.148 mmol h−1 cm−2) and [email protected] (0.076 mmol h−1 cm−2). Moreover, [email protected] 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 [email protected], 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.