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

Abstract

AbstractElectrocatalytic nitrite (NO2−) reduction reaction (NO2−RR) for ammonia (NH3) synthesis is a promising alternative for NO2− resource utilization. Herein, a dual‐site copper‐cobalt oxide catalyst is reported for the efficient electrocatalytic reduction of NO2− to NH3, exhibiting NH3 Faradaic efficiency that remained above 95% (0.1 m NaNO2) over a wide potential window (−0.1 to −0.6 V vs reversible hydrogen electrode, vs RHE). More importantly, the high NH3 Faradaic efficiency maintains an over 85% (−0.1 to −0.3 V vs RHE) at a low concentration of NaNO2 (0.01 m). Theoretical calculations demonstrate that CuO serves the *NO2 to *NO and is subsequently converted to NH3 on Co3O4. 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 NO2− and EG.