Hierarchical Electronic Structure Modulation of Cu‐Co Dual‐Site and CNT Tandem Interface Enables Highly Efficient Electrocatalytic Ammonia Synthesis

ABSTRACT Electrocatalytic reduction of nitrate to ammonia (NO 3 RR) is a highly efficient dual strategy that can both reduce NO 3 − pollution and achieve sustainable NH 3 production. To overcome the low efficiency bottleneck under neutral electrolyte conditions, this study designed a tandem catalyst Cu‐Co‐O/CNT‐2 based on carbon nanotubes (CNT). By anchoring the Cu‐Co dual sites on the CNT support, the electronic structure and reaction pathway were optimized. At −0.9 V vs RHE, the Cu‐Co‐O/CNT‐2 catalyst exhibited an ammonia yield of 5.088 mg h −1 cm −2 and a Faradaic efficiency of 81.83%, significantly improving the NO 3 RR performance. In situ FTIR characterization revealed the dominant NHO pathway and successfully captured the * NH 2 OH intermediate. DFT calculations and in situ EPR analysis further indicate that the Cu‐Co‐O active sites preferentially adsorb * NO x , while CNT effectively lowers the reaction energy barrier and enhances the multi‐electron conversion efficiency by promoting the upward shift of the d‐band center (−1.837 eV), thus driving the deoxygenation and stepwise hydrogenation of NO 3 − to NH 3 . In summary, this study provides theoretical support for the design of efficient tandem catalytic systems and offers new insights into ammonia generation and resource conversion in the NO 3 RR reaction.