Electrocatalytic Systems for NO_x Valorization in Organonitrogen Synthesis

Abstract

Inorganic nitrogen oxide (NOx) species, such as NO, NO2, NO3−, NO2− generated from the decomposition of organic matters, volcanic eruptions and lightning activated nitrogen, play important roles in the nitrogen cycle system and exploring the origin of life. Meanwhile, excessive emission of NOx gases and residues from industry and transportation causes troubling problems to the environment and human health. How to efficiently handle these wastes is a global problem. In response to the growing demand for sustainability, scientists are actively pursuing sustainable electrochemical technologies powered by renewable energy sources and efficient utilization of hydrogen energy to convert NOx species into high‐value organonitrogen chemicals. In this minireview, recent advances of electrocatalytic systems for NOx species valorization in organonitrogen synthesis are classified and described, such as amino acids, amide, urea, oximes, nitrile etc., that have been widely applied in medicine, life science and agriculture. Additionally, the current challenges including multiple side reactions and complicated paths, viable solutions along with future directions ahead in this field are also proposed. The coupling electrocatalytic systems provide a green mode for fixing nitrogen cycle bacteria and bring enlightenment to human sustainable development.

Synthesis of Hydroxylamine via Ketone-Mediated Nitrate Electroreduction

“…Manufacturing nitrogenous chemicals emit about 400 million metric tons of CO 2 annually, which is incompatible with carbon neutrality and sustainability goals. − Hydroxylamine (HA, NH 2 OH) is a key compound in various fields, such as the semiconductor industry, material synthesis, photographic development, and biomedicine research, as well as a potential hydrogen carrier. − Currently, the synthesis of HA is dominated by NH 3 oxidation or NO hydrogenation under harsh conditions with large energy consumption and carbon emission (Scheme ). − Noble metal catalysts and complicated equipment are also required to improve the conversion efficiency and the HA yield.…”

Efficient electrochemical coupling of nitrate and biomass-derived acetone to acetoxime at a high current density over a Zn/Cu hexagonal nanosheet catalyst

“…Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. E-mail: ywzhang@pku.edu.cn nitrite; 6 (3) as an organic synthesis intermediate, it belongs to a crucial class of organonitrogen compounds used in pharmaceuticals, pesticides, fuels, and organosilane coupling agent synthesis; 7,8 (4) it is also used as an analytical reagent for measuring Ni and Co metal elements. 9,10 Currently, the traditional synthesis of acetoxime mainly involves two steps.…”

“…Acetoxime, a significant chemical raw material, is employed in a multitude of industrial applications. 1–3 (1) Due to its low toxicity and high reducibility, it is commonly employed as a boiler chemical deoxygenation agent, replacing the more toxic hydrazine; 4,5 (2) as a passivator after boiler acid pickling, it effectively prevents secondary corrosion of metals, and avoids the use of toxic passivators such as ammonia and sodium nitrite; 6 (3) as an organic synthesis intermediate, it belongs to a crucial class of organonitrogen compounds used in pharmaceuticals, pesticides, fuels, and organosilane coupling agent synthesis; 7,8 (4) it is also used as an analytical reagent for measuring Ni and Co metal elements. 9,10 Currently, the traditional synthesis of acetoxime mainly involves two steps.…”

“…43 Since Jiao successfully constructed acetamide from CO and NH 3 using an electrocatalytic method over Cu-based catalysts, 44 the green synthesis of organonitrogen compounds using readily available carbon/nitrogen-containing small molecules under mild conditions has become an emerging field. 8,45–48 In the field of electrosynthesis of oximes, researchers have successfully synthesized cyclohexanone oxime, 49,50 benzaldoxime, 51 formaldoxime, 52 cyclopentanoxime, 53 and pralidoxime 42 from C-containing (cyclohexanone, benzaldehyde, formaldehyde, acetone, pyridine aldehyde) and N-containing (NO 3 − , NO 2 − , NO) small molecules as reactants. Although there has been some progress in the electrocatalytic C–N/CN field, this reaction typically entails multi-step elementary reactions, rendering it a complex catalytic system.…”