Atomic-dispersed copper simultaneously achieve high-efficiency removal and high-value-added conversion to ammonia of nitrate in sewage

Abstract

Environmentally friendly electrochemical reduction pathways from NO3− to NH3 or N2 have provided feasible strategy into the green production of ammonia or the treatment of nitrate wastewater. Here, we anchored single-atom Cu with boron carbon nitride on carbon nanotube (BCN@Cu/CNT), and achieved the efficient operation of electrochemical nitrate reduction reaction (NIRR). BCN@Cu/CNT can efficiently catalyze the selective conversion of high-concentration nitrate into high-value-added ammonia, where the ammonia yield rate and Faradaic efficiency are as high as 172,226.5 μg h−1 mgcat.−1 and 95.32% (at −0.6 V), respectively. BCN@Cu/CNT also shows the ability to efficiently remove low-concentration nitrates in sewage. Specifically, here only takes 5 h to nearly 100% (99.32%) eliminate NO3- (50 mg L−1) in sewage without any residual NO2−. The excellent catalytic activity and physicochemical stability of BCN@Cu/CNT for NIRR suggest the promising industrial application prospects, including the green production of ammonia and the purification of nitrate wastewater.