Ambient Synthesis of Cyclohexanone Oxime via In Situ Produced Hydrogen Peroxide over Cobalt-Based Electrocatalyst.

Cyclohexanone oxime, a critical precursor for nylon-6 production, is traditionally synthesized via the hydroxylamine method under industrial harsh conditions. Here is present a one-step electrochemical integrated approach for the efficient production of cyclohexanone oxime under ambient conditions. This approach employed the coupling of in situ electro-synthesized HO over a cobalt (Co)-based electrocatalyst with the titanium silicate-1 (TS-1) heterogeneous catalyst to achieve the cyclohexanone ammoximation process. The cathode electrocatalyst is consisted of atomically dispersed Co sites and small Co nanoparticles co-anchored on carboxylic multi-walled carbon nanotubes (CoSAs/SNPs-OCNTs), which delivered superior electrocatalytic activity toward the two-electron oxygen reduction reaction (2e ORR) with high-efficient HO production in 0.1 m sodium phosphate (NaPi). Theoretical calculations revealed that the introduction of Co nanoparticles effectively optimized the binding strength of OOH species on Co atomic sites, thus facilitating the 2e ORR. The subsequent tandem catalytic system achieved a high cyclohexanone conversion of 71.7% ± 1.1% with a cyclohexanone oxime selectivity of 70.3% ± 0.6%. In this system, the TS-1 catalyst effectively captured the OOH intermediate and activated the in situ generated HO to form Ti-OOH species, which promoted the formation of hydroxylamine and thereby enhanced the oxime production performance.