Electrocatalytic nitrate reduction to ammonia on defective Au1Cu (111) single-atom alloys

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 (VCu- Au1Cu SAAs), which exhibited superior NH3 Faradaic efficiency (98.7%) with a production rate of 555 mu g 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 VCu-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.

Automated summary

This study designed and prepared Au1Cu (111) single-atom alloys with superior performance for electrocatalytic reduction of nitrate to ammonia in wastewater. The Au1Cu catalyst showed high NH3 production rate and Faradaic efficiency, and exhibited excellent durability without significant activity decay. Furthermore, the produced ammonia can be easily recovered through membrane distillation.