Descriptor-guided unlocking of efficient nitrate-to-ammonia electroreduction on copper-based single-atom alloys

The electrocatalytic nitrate reduction reaction (e-NO₃^-RR) is an effective way to address nitrate pollution and offers an attractive strategy for ammonia synthesis under mild conditions. However, the identification of novel catalysts via computational guidance remains a central challenge in this field. Herein, a series of single-atom transition-metals (TMs)-alloyed copper-based single-atom alloys (SAAs) were used as model catalysts (TM₁-Cu(111)) for e-NO₃^-RR. Among them, three TM₁-Cu(111) catalysts (TM = Ti, Zr, and Nb) had outstanding catalytic activity, with low limiting potentials of -0.20, -0.39, and -0.32 V, respectively. Furthermore, these candidates effectively suppressed the hydrogen evolution reaction and demonstrated excellent thermodynamic stability. To clarify the activity trend of e-NO₃^-RR on Cu-based SAAs, the adsorption strength of the NO intermediate was identified as an effective descriptor. This work provides computational guidance for the rational design of high-performance e-NO₃^-RR catalysts.