Sustainable conversion of alkaline nitrate to ammonia at activities greater than 2 A cm−2
Wanru Liao, Jun Wang, Ganghai Ni, Kang Liu, Changxu Liu, Shanyong Chen, Qiyou Wang, Yingkang Chen, Tao Luo, Xiqing Wang, Yanqiu Wang, Wenzhang Li, Ting‐Shan Chan, Chao Ma, Hongmei Li, Ying Liang, Weizhen Liu, Junwei Fu, B. Xi, Min Liu
Abstract
Abstract Nitrate (NO 3 ‒ ) pollution poses significant threats to water quality and global nitrogen cycles. Alkaline electrocatalytic NO 3 ‒ reduction reaction (NO 3 RR) emerges as an attractive route for enabling NO 3 ‒ removal and sustainable ammonia (NH 3 ) synthesis. However, it suffers from insufficient proton (H + ) supply in high pH conditions, restricting NO 3 ‒ -to-NH 3 activity. Herein, we propose a halogen-mediated H + feeding strategy to enhance the alkaline NO 3 RR performance. Our platform achieves near-100% NH 3 Faradaic efficiency (pH = 14) with a current density of 2 A cm –2 and enables an over 99% NO 3 – -to-NH 3 conversion efficiency. We also convert NO 3 ‒ to high-purity NH 4 Cl with near-unity efficiency, suggesting a practical approach to valorizing pollutants into valuable ammonia products. Theoretical simulations and in situ experiments reveal that Cl-coordination endows a shifted d -band center of Pd atoms to construct local H + -abundant environments, through arousing dangling O-H water dissociation and fast *H desorption, for *NO intermediate hydrogenation and finally effective NO 3 ‒ -to-NH 3 conversion.