Electrocatalytic reduction of nitrite to ammonia on undercoordinated Cu

Abstract

Electrocatalytic NO₂⁻-to-NH₃ reduction (NO₂RR) has emerged as an intriguing route for simultaneous mitigation of harmful nitrites and production of valuable NH₃. Herein, we design for the first time undercoordinated Cu nanowires (u-Cu) as an efficient and selective NO₂RR electrocatalyst, delivering the maximum NO₂⁻-to-NH₃ faradaic efficiency of 94.7% and an ammonia production rate of 494.5 μmol h⁻¹ cm⁻² at −0.7 V vs. RHE. Theoretical calculations reveal that the created undercoordinated Cu sites on u-Cu can enhance NO₂⁻ adsorption, boost NO₂⁻-to-NH₃ energetics and restrict competitive hydrogen evolution, thereby enabling the active and selective NO₂RR.