A Pickering-emulsion-droplet-integrated electrode for the continuous-flow electrosynthesis of oximes
摘要
The electrosynthesis of cyclohexanone oxime from cyclohexanone and nitrogen oxide is a promising, sustainable industrial process. However, it is hindered by high mass transport resistance in the biphasic reaction and the competitive hydrogenation of hydroxylamine, resulting in low Faradaic efficiency and production rates. Here we design a Pickering-emulsion-droplet-integrated electrode to facilitate the continuous-flow electrocatalytic synthesis of cyclohexanone oxime. The emulsion droplets provide an ideal localized interfacial microenvironment for electrocatalysts, characterized by the orientational ordering of water molecules and incomplete interfacial hydrogen bonding with cyclohexanone, which enhances the efficiency of the biphasic oximation process. Additionally, the droplet-based network formed on the electrodes establishes an efficient charge-transfer channel, enabling continuous production of cyclohexanone oxime at high operating current densities and allowing for continuous product collection without the need for additional demulsification steps. Our system achieves production rates (100 mA cm−2, 0.78 mmol h−1 cm−2) approximately five times greater than those reported for previous catalysts, with a Faradaic efficiency of 83.8%, long-term operational stability (100 h) and scalability for the synthesis of 10 g of cyclohexanone oxime, making it promising for industrial application.