Li, Z., Li, X., Zhou, H., Xu, Y., Xu, S. M., Ren, Y., Yan, Y., Yang, J., Ji, K., Li, L., Xu, M., Shao, M., Kong, X., Sun, X., Duan, H.*
Nat Commun 2022, 13, 5009
Adipic acid is an important building block of polymers, and is commercially produced by thermo-catalytic oxidation of ketone-alcohol oil (a mixture of cyclohexanol and cyclohexanone). However, this process heavily relies on the use of corrosive nitric acid while releases nitrous oxide as a potent greenhouse gas. Herein, we report an electrocatalytic strategy for the oxidation of cyclohexanone to adipic acid coupled with H2 production over a nickel hydroxide (Ni(OH)2) catalyst modified with sodium dodecyl sulfonate (SDS). The intercalated SDS facilitates the enrichment of immiscible cyclohexanone in aqueous medium, thus achieving 3.6-fold greater productivity of adipic acid and higher faradaic efficiency (FE) compared with pure Ni(OH)2 (93% versus 56%). This strategy is demonstrated effective for a variety of immiscible aldehydes and ketones in aqueous solution. Furthermore, we design a realistic two-electrode flow electrolyzer for electrooxidation of cyclohexanone coupling with H2 production, attaining adipic acid productivity of 4.7 mmol coupled with H2 productivity of 8.0 L at 0.8 A (corresponding to 30 mA cm−2) in 24 h.