Constructing a Bifunctional Heterointerface Realizes Superior Electroreduction of Nitrate-Enriched Wastewater with Wide Concentrations for Ammonia Production
Mingyu Cheng, Zechuan Dai, Yanxu Chen, Huaikun Zhang, Bocheng Zhang, Pingyi Feng, Yafei Feng, Yangyang Zhang, Nazir Ahmad, Genqiang Zhang
Abstract
Electrochemical nitrate (NO 3 – ) reduction reaction (NO 3 RR), emerges as an ingenious approach to the alternative Haber–Bosch process for ammonia (NH 3 ) synthesis, while the investigation on high performance catalysts remains difficult in regulating NO 3 – adsorption. Herein, we develop a feasible strategy that can simultaneously modulate the adsorption behavior of NO 3 – and thereby lower the energy barrier for NH 3 formation by constructing Cu/Cu 2 O heterointerface with in situ electrochemical transformation of Cu 2 (OH) 2 CO 3, realizing over 90% Faradaic efficiency (FE) under concentrations from 50 to 1400 ppm, with superior NH 3 yields (0.936–11.21 mg h –1 mg –1 ). Synchrotron radiation–Fourier transform infrared spectroscopy) and density functional theory calculations decipher that the Cu/Cu 2 O heterointerface can realize the balanced adsorption capability of NO 3 – and facilitate the formation of the *NOH intermediate to largely lower the energy barrier of the rate-determining step. The two-electrode flow cell measurement demonstrates its efficiency and practicability to produce a high purity NH 4 Cl solid and NH 3 solution. This work not only provides a rationale for catalyst design for the NO 3 RR but also indicates the feasibility of converting wastewater NO 3 – into valuable NH 3 products.