Breaking Linear Scaling Relation Limitations on a Dual‐Driven Single‐Atom Copper‐Tungsten Oxide Catalyst for Ammonia Synthesis

Abstract Electrocatalytic reduction of nitrate (NO 3 − , NO3RR) on single‐atom copper catalysts (Cu‐SACs) offers a sustainable approach to ammonia (NH 3 ) synthesis using NO 3 − pollutants as feedstocks. Nevertheless, this process suffers from inferior NO3RR kinetics and nitrite accumulation owing to the linear scaling relation limitations for SACs. To break these limitations, a single‐atom Cu‐bearing tungsten oxide catalyst (Cu 1 /WO 3 ) was developed, which mediated a unique dual‐driven NO3RR process. Specifically, WO 3 dissociated water molecules and supplied the Cu 1 site with ample protons, whereas the Cu 1 site in an electron‐deficient state converted NO 3 − to NH 3 efficiently. The Cu 1 /WO 3 delivered an impressive NH 3 production rate of 1274.4 mg N h −1 g Cu −1 , a NH 3 selectivity of 99.2%, and a faradaic efficiency of 93.7% at −0.60 V, surpassing most reported catalysts. Furthermore, an integrated continuous‐flow system consisting of a NO3RR cell and a vacuum‐driven membrane separator was developed for NH 3 synthesis from nitrate‐contaminated water. Fed with the Yangtze River water containing ∼22.5 mg L −1 of NO 3 − ‐N, this system realized an NH 3 production rate of 325.9 mg N h −1 g Cu −1 and a collection efficiency of 98.3% at energy consumption of 17.11 kwh g N −1 . This study provides a new dual‐driven concept for catalyst design and establishes a foundation for sustainable NH 3 synthesis from waste.