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

• Published in: Advanced energy materials 2024-03, Vol.14 (11), p.n/a
• Main Authors: Niu, Zhaodong, Fan, Shiying, Li, Xinyong, Chen, Guohua
• Format: Article
• Language: English
• Subjects: Ammonia; ammonia synthesis; Anodizing; Chemical reduction; Cobalt oxides; Copper oxides; Co‐upcycling; electrocatalytic; Electrodes; Energy consumption; Ethylene glycol; ethylene glycol oxidation; nitrite reduction reaction; Nitrogen dioxide; Oxidation; Resource utilization; Sodium nitrite
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202303515

Electrocatalytic 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. The authors construct a dual‐site Cobalt–Copper oxides electrocatalyst (CuO/Co3O4) for co‐upcycling of nitrite (NO2−) and ethylene glycol (EG) to ammonia and formate. In a two‐electrode system, NO2−RR coupled EGOR significantly reduces cell voltage (ΔU10mAcm−2=480mV)$( {{\mathrm{\Delta U}}_{{\mathrm{10mA\ c}}{{\mathrm{m}}}^{{\mathrm{ - 2}}}\ = \ 480{\mathrm{\ mV}}} )$ and energy consumption (>23%).