Single-Atom/Nanocluster Synergistic Electrode Derived From Phthalocyanine Salts for Efficient Electroreduction of...

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 NH₃ 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 NO₃ ^- adsorption, reducing the adsorption energy from 0.66 eV on isolated Cu atoms to -1.34 eV, thereby accelerating the initial NO₃RR kinetics. Moreover, the free-energy barrier of the rate-limiting step is substantially lower on Cu nanoclusters (*NO₂ → *NO₂H, +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 NH₃ 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.