Single‐Atom/Nanocluster Synergistic Electrode Derived From Phthalocyanine Salts for Efficient Electroreduction of Nitrate to Ammonia

ABSTRACT Electrochemical nitrate reduction reactions to ammonia represent a promising route to close the global nitrogen cycle, but their practical implementation is hindered by the low conversion efficiency of existing electrocatalysts. Herein, we develop a multiscale regulation strategy to construct a copper‐cobalt co‐modified carbon‐nanofiber‐based self‐supporting electrode (CuCo‐CNF), in which Cu nanoclusters and Co single atoms are selectively anchored using phthalocyanine salts as precursors. Benefiting from the synergistic interaction between dual active sites, the CuCo‐CNF electrode exhibits an outstanding NH 3 yield rate of 11.3 mg h −1 cm −2 with a Faradaic efficiency of 95.84% at −0.7 V versus RHE, outperforming carbon‐nanofiber‐based electrodes. It has been demonstrated that Cu nanoclusters significantly enhance NO 3 − adsorption, reducing the adsorption energy from 0.66 eV on isolated Cu atoms to −1.34 eV, thereby accelerating the initial NO 3 RR kinetics. Moreover, the free‐energy barrier of the rate‐limiting step is substantially lower on Cu nanoclusters (*NO 2 → *NO 2 H, +0.59 eV) than on Cu single atoms (*NO → *NOH, +1.02 eV). Meanwhile, the incorporation of cobalt heteroatoms further promotes active hydrogen generation, further enhancing both reaction rate and NH 3 selectivity. This work establishes an effective strategy for constructing self‐supporting electrodes and offers valuable mechanistic insights into efficient and selective electrocatalytic nitrate‐to‐ammonia conversion.