Electron-deficient CoO induced charge redistribution on CuCoO-NC nanohybrid for electrocatalytic reduction of nitrate to ammonia

Abstract

The use of electrochemical tactics to reduce nitrate to the valorized product ammonia has become the hot topic. Recently, the synergistic effect of metal/metal oxide is provided to significantly enhance the electrocatalytic performance of nitrate reduction as opposed to monometallic catalyst. In this work, a reticulated fibre structure with Cu/CoO nanoparticles (CuxCoyO-NC) was prepared for electrocatalytic nitrate reduction (NO3-RR) to ammonia. The optimized catalyst (Cu1Co1O-NC) displayed brilliant performance for NO3-RR with high Faraday efficiency (FE) of 97.9 %, the excellent NH3 yield rate of 0.45 mmol h−1 cm−2, prominent NH3 selectivity of 98.4 % and efficient NO3– conversion of 99.2 % at −0.79 V vs reversible hydrogen electrode (RHE). Besides, Cu1Co1O-NC also exhibits the potential for uranium recovery from simulated wastewater containing nitrate and uranyl ions with a total yield of 508 mg ammonium diuranate after i-t measurement for 6 times. This work not only provides an efficient catalyst for reduction nitrate but also proposes the sustainable method for uranium containing sewage realizing nitrogen cycle.