Electrocatalytic synthesis of adipic acid coupled with H2 production enhanced by a ligand modification strategy

Abstract

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.

Efficient Electrocatalytic Oxidation of Glycerol via Promoted OH* Generation over Single-Atom-Bismuth-Doped Spinel Co3O4

“…As shown in Figure S42, the proportions of glycerate (GCA), glycolate (GLA), and glyoxylate (GOA) increase first and then decrease, implying that they may be the important intermediates for GOR to formate, as supported by 1 H and two-dimensional (2D) heteronuclear singular quantum correlation (HSQC) nuclear magnetic resonance (NMR) (Figures S43 and S44). In terms of the separation of the organic acids, the possible methods are acid neutralization and electrocatalysis-coupling–electrodialysis (EC-ED) …”

“…In terms of the separation of the organic acids, the possible methods are acid neutralization 58 and electrocatalysis-coupling−electrodialysis (EC-ED). 59 The LSV curves (Figure S45) and chronoamperometric experiments using the possible intermediates as substrates over Co 3 O 4 and Bi-Co 3 O 4 were conducted, which allows us to depict a complete reaction pathway of GOR (Note S2, Tables S9 and S10). Based on the above results including the species distribution versus time at 1.65 V vs RHE in Figure S42 and previous reports, 5,19,60 the reaction pathways of glycerol electro-oxidation over Bi-Co 3 O 4 are illustrated in Figure 5.…”

Advanced electrocatalytic systems for enhanced atom/electron utilization

“…High value chemicals, such as alkane, imine, and carboxylic acid chemicals, can be obtained by the electrocatalytic oxidation of aldehydes. 69,70 Zhang and co-workers 71 designed a carbohydrate-universal catalyst of Co 3 FeP x @NF for electrocatalytic oxidation of various carbohydrates (COR), including glucose, fructose, maltose, and sucrose, which exhibited a much lower potential than that required for the OER. A HER-GOR coupled coelectrolysis system has been assembled by using a 2-electrode system that can reach a high current density of over 200 mA cm À2 .…”

Electrocatalytic Reduction of CO2 Coupled with Organic Conversion to Selectively Synthesize High‐Value Chemicals

“…[58] Li et al reported a highly selective electrooxidation of ketone-alcohol (KA) oil to adipic acid by sodium dodecyl sulfonate (SDS)-modified nickel hydroxide (Ni(OH) 2 ). [59] Mahmoudian et al used ceria electrocatalyst (Pd/CÀ CeO 2 ) to drive the electrooxidation of 1,3propandiol and obtained 77 % of selectivity for acrylate at a cell temperature of 80 °C and at a fixed cell potential of 400 mV. [60] It should be noted that although the efficiency of propylene electrooxide to propylene oxide is still relatively low, [61] with the help of the design of new catalysts and the exploration of reaction environments, this reaction may be economically feasible to match CO 2 RR.…”

“…Li et al. reported a highly selective electrooxidation of ketone‐alcohol (KA) oil to adipic acid by sodium dodecyl sulfonate (SDS)‐modified nickel hydroxide (Ni(OH) 2 ) [59] . Mahmoudian et al.…”