Steering pH‐Dependent Pathways on Unconventional Phase Alloy Nanostructures for Universal Nitrate Electroreduction

Electrocatalytic nitrate reduction reaction (NO 3 RR) to ammonia has been regarded as a sustainable strategy for industrial wastewater denitrification and fertilizer manufacturing toward green nitrogen circulation. However, complex pH conditions of practical nitrate wastewater result in poor catalyst universality, severely hindering their long‐term deployment. Furthermore, the underlying reaction mechanisms in different pH scenarios remain ambiguous, obstructing the rational design of pH‐universal electrocatalysts. Here we propose a crystal phase engineering approach to enhance the NO 3 RR performance in complex pH scenarios. The as‐designed unconventional face‐centered cubic (fcc) RuW nanoflowers exhibit excellent ammonia Faradaic efficiency (FE) above 91.0% over a wide pH range of 1–14, with the largest yield rate of 40.1 mg h −1 mg cat −1 . Mechanism studies indicate that fcc RuW nanoflowers adaptively steer reaction pathways toward diverse pH environments. Based on the long‐term durability test at an industrial‐level current density of 300 mA cm −2 for 200 h in flow reactors, techno‐economic analysis with the optimized process further demonstrates promising application potential. This study not only provides a fundamental insight into the pH‐dependent mechanisms of nitrate electroreduction, but also offers a robust catalyst design approach toward complex practical conditions.