Breaking Linear Scaling Relation Limitations on a Dual‐driven Single‐atom Copper/Tungsten Oxide Catalyst for Ammonia Synthesis

Electrocatalytic reduction of nitrate (NO3‐, NO3RR) on single‐atom copper catalysts (Cu‐SACs) offers a sustainable approach to ammonia (NH3) synthesis using NO3‐ 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 (Cu1/WO3) was developed, which mediated a unique dual‐driven NO3RR process. Specifically, WO3 dissociated water molecules and supplied the Cu1 site with ample protons, while the Cu1 site in an electron‐deficient state converted NO3‐ to NH3 efficiently. The Cu1/WO3 delivered an impressive NH3 production rate of 1274.4 mgN h‐1 gCu‐1, a NH3 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 NO3RR cell and vacuum‐driven membrane separator was developed for NH3 synthesis from nitrate‐contaminated water. Fed with the Yangtze River water containing ~22.5 mg L‐1 of NO3‐‐N, this system realized an NH3 production rate of 325.9 mgN h‐1 gCu‐1 and a collection efficiency of 98.3% at energy consumption of 17.11 kwh gN‐1. This study provides a new dual‐driven concept for catalyst design and establishes a foundation for sustainable NH3 synthesis from waste.