Pulse‐Electrodeposited Single‐Atom Alloys with Steered Surface Hydrogenation Dynamics for Air‐to‐Fertilizer Synthesis

Abstract Harnessing renewable electricity to transform abundant environmental resources into fertilizers is central to sustainable development. Electrochemical nitrate‐to‐ammonia conversion provides a promising route, yet its efficiency is constrained by the elusive surface hydrogenation dynamics governing multi‐step *NO x reduction. Here, a cooperative descriptor (Ψ) derived from large‐language‐models‐assisted mining and energetic analysis successfully identifies NiCu single‐atom alloys (SAAs) as optimal catalysts. Pulse electrodeposition delivers atomically dispersed alloys with tunable structures, achieving a maximum Faradaic efficiency (FE) of ∼95% and yield rate (YR) of ∼11.4 mg h −1 cm −2 . In situ surface‐interrogation scanning electrochemical microscopy (SI‐SECM) provides quantitative information on the time‐resolved surface‐active hydrogen (*H) generation‐consumption and *NO x hydrogenation rate constants (NiCu > CoCu ≫ MnCu ≈ FeCu > Cu), directly aligning surface kinetics with selectivity. Theoretical investigations further confirmed that Ni doping lowers the barriers for *H formation and *NO x hydrogenation. A plasma‐electrochemical‐CO 2 capture system demonstrated continuous “air‐to‐fertilizer” conversion with reduced energy consumption and potential net‐negative emissions. These results establish a transferable design rule that bridges theoretical descriptors with operando hydrogenation dynamics, providing a mechanistic foundation and practical pathway toward scalable, zero‐carbon fertilizer production.