Electrocatalytic Co‐Upcycling of Nitrite and Ethylene Glycol over Cobalt–Copper Oxides

Abstract Electrocatalytic nitrite (NO 2 − ) reduction reaction (NO 2 − RR) for ammonia (NH 3 ) synthesis is a promising alternative for NO 2 − resource utilization. Herein, a dual‐site copper‐cobalt oxide catalyst is reported for the efficient electrocatalytic reduction of NO 2 − to NH 3 , exhibiting NH 3 Faradaic efficiency that remained above 95% (0.1 m NaNO 2 ) over a wide potential window (−0.1 to −0.6 V vs reversible hydrogen electrode, vs RHE). More importantly, the high NH 3 Faradaic efficiency maintains an over 85% (−0.1 to −0.3 V vs RHE) at a low concentration of NaNO 2 (0.01 m ). Theoretical calculations demonstrate that CuO serves the * NO 2 to * NO and is subsequently converted to NH 3 on Co 3 O 4 . Coupled anodic ethylene glycol (EG) oxidation reaction endows low cell voltage (ΔU = 480 mV, 10 mA cm −2 ) and energy consumption saving (>23%) in a two‐electrode system. This work provides a reference for a co‐upcycling electrolyzer for NO 2 − and EG.