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, whereas 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 mg_N h^-1 g_Cu ^-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 a NO3RR cell and a 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 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 NH₃ synthesis from waste.