Accelerating ammonia synthesis in a membraneless flow electrolyzer through coupling ambient dinitrogen oxidation and water splitting

Jing-Jing Lv; Zhe Li; Jiaju Fu; Wenlei Zhu

doi:10.1016/j.isci.2023.106407

Accelerating ammonia synthesis in a membraneless flow electrolyzer through coupling ambient dinitrogen oxidation and water splitting

iScience. 2023 Mar 21;26(4):106407. doi: 10.1016/j.isci.2023.106407. eCollection 2023 Apr 21.

Authors

Jing-Jing Lv¹, Zhe Li², Jiaju Fu², Wenlei Zhu²

Affiliations

¹ Wenzhou Key Lab of Advanced Energy Storage and Conversion, Zhejiang Province Key Lab of Leather Engineering, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China.
² School of Chemistry and Chemical Engineering, School of Environment, State Key Laboratory of Analytical Chemistry for Life Science, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210023, China.

Abstract

An electrochemical approach for ammonia production is successfully developed by coupling the anodic dinitrogen oxidation reaction (NOR) and cathodic hydrogen evolution reaction (HER) within a well-designed membraneless flow electrolyzer. The obtained reactor shows the preferential yield of ammonia over nitrogen oxides on the vanadium nitride catalyst surface. At an applied oxidation potential of 2.25 V versus the reversible hydrogen electrode (vs RHE), a promoted ammonia production rate and Faradaic efficiency (FE) were obtained with 9.9 mmol g^-1 h^-1 (0.029 mmol cm^-2 h^-1) and 4.8%, respectively. Besides, the negative affection of ammonia contamination is efficiently alleviated. Density functional theory calculations revealed that the thermodynamic energy needed to produce ammonia (-0.63 eV) is far lower than that of producing nitrogen oxide (0.96 eV) from hydrogenated nitrogen oxides [∗N₂OH] splitting, confirming the coupling of NOR and HER.

Keywords: Catalysis; Materials chemistry; Materials science.