Boosting electrochemical nitrite–ammonia conversion properties by a Cu foam@Cu 2 O catalyst

CF@Cu 2 O is a superb NO 2 − reduction reaction electrocatalyst, achieving high-efficiency electrosynthesis of ammonia from nitrite with an excellent ammonia yield of 7510.73 μg h − 1 cm − 2 and Faraday efficiency of 94.21%.