Alloying Pd with Ru enables electroreduction of nitrate to ammonia with ∼100% faradaic efficiency over a wide potential window.

Electrocatalytic nitrate (NO) reduction reaction (eNORR) to ammonia under ambient conditions is deemed a sustainable route for wastewater treatment and a promising alternative to the Haber-Bosch process. However, there is still a lack of efficient electrocatalysts to achieve high NH production performance at wastewater-relevant low NO concentrations. Herein, we report a PdRu bimetallic nanocrystal (NC) electrocatalyst capable of exhibiting an average NH FE of ∼100% over a wide potential window from 0.