Asymmetric Manganese Sites in Covalent Organic Frameworks for Efficient Nitrate‐to‐Ammonia Electrocatalysis

The electrocatalytic nitrate reduction reaction (NO3−RR) holds tremendous potential for remediating NO3− pollution in groundwater while enabling clean ammonia (NH3) production. However, most catalysts achieve high conversion efficiency relying on high NO3− concentrations. How to catalyze the NO3−RR with low concentration of NO3− is still a challenge due to the competing hydrogen evolution reaction (HER). To address this limitation, we constructed a novel asymmetric isolated Mn atom based on N‐coordination covalent organic framework (COF) (ImPy‐COF‐Mn), for efficient NO3−RR at a low NO3− concentration of 2 mg mL−1. This bidentate‐coordinated COF featured a robust and chemically stable framework, while the synergistic interaction between asymmetric imine N and pyridine N modified the charge distribution of Mn atoms to optimize catalytic efficiency. ImPy‐COF‐Mn demonstrated remarkable catalytic performance, with 95.64% NH3 selectivity and a maximum NH3 yield rate of 1927 mmol h−1 gcat.−1, exceeding the corresponding parameters of symmetric Mn sitesby factors of 1.27 and 1.41, respectively. In situ ATR‐FTIR measurements and theoretical calculations revealed that the asymmetric isolated Mn facilitated a reduction in the energy barrier for *NO‐to‐*NOH conversion, and thus contributed to higher activity and selectivity.