Abstract
Electrocatalytic reduction of nitrate (NO3~-) to ammonia (NH3) in wastewater is a promising economic process for NH3 synthesis. This work designed and prepared Au1Cu (111) single-atom alloys with surface Cu vacancies (V_(Cu-) Au1Cu SAAs), which exhibited superior NH3 Faradaic efficiency (98.7%) with a production rate of 555 μg h~(-1) cm~(-2) at -0.2 V vs. RHE, while negligible activity decay was found after a durability test. Meanwhile, 97% of produced NH3 can be recovered by a simple membrane distillation. Characterizations evidence that electron migration from Cu to Au atoms creates electron-deficient Cu active sites in V_(Cu)-Au1Cu SAAs, which promote the generation of active hydrogen species (*H) that can readily hydrogenate NO3~-. Theoretical calculation reveals that the bi-functional Cu sites not only promote the activation of water to produce *H but also lower the energy barrier of *NH3 desorption from the catalyst surface.
NSTL