Nano-V2O5/Ti porous membrane electrode with enhanced electrochemical activity for the high-efficiency oxidation of cyclohexane.

The selective oxidation of cyclohexane (CHA) is still a significant challenge in the field of current catalysis chemistry and chemical industry. Here, nano-V2O5/Ti porous membrane electrodes with different morphologies, i.e., nanorods (NRs), nanosheets (NSs), and nanoparticles (NPs), were prepared by loading nano-V2O5 onto porous Ti membranes. Simultaneously, a nano-V2O5/Ti membrane electrode was employed to constitute an electrocatalytic membrane reactor (ECMR) for CHA oxidation. Results indicated that the electrochemical performance was significantly associated with the morphology of the nano-V2O5 catalysts on the membrane electrode. ECMR with V2O5 NSs/Ti electrode exhibited superior properties. Excellent electrochemical activity was obtained in the application of CHA oxidation with 28.4% conversion and 99.9% selectivity to cyclohexanone and cyclohexanol (KA oil), which is better than most noble-metal-based catalysts reported in the literature under aerobic reaction conditions. Further, a prominent catalytic activity (10.5% conversion and 99.5% selectivity to KA oil) was first achieved even under 0 °C. The preferable electrocatalytic performance of V2O5 NSs/Ti electrode for CHA oxidation was attributed to the large effective electrocatalytic surface area, high electron transfer rate, and high rate of hydroxyl radical (ṖOH) generation. Furthermore, the mechanism of CHA oxidation was explored. It was established that the valence change of V catalysts is an essential step during the selective oxidation of CHA by ECMR. Moreover, the V2O5 NSs/Ti electrode displayed excellent stability of oxidation during the selective oxidation of CHA. Therefore, our research opens up a new avenue toward the fundamental understanding and design of nanocatalysts in heterogeneous and electrochemical catalysis. [ABSTRACT FROM AUTHOR]