SiO2 supported Co3O4 catalyst for selective oxidation of cyclohexene with molecular oxygen

In this work, highly dispersed cobalt oxide nanoparticles on SiO2 support were prepared by a facile impregnation method and explored for aerobic selective oxidation of cyclohexene to 2-cyclohexene-1-one under base-free conditions. Among various compositions of Co3O4/SiO2 catalysts (0.5 to 5 wt% Co3O4) investigated, a 1 wt% Co3O4/SiO2 catalyst showed superior cyclohexene conversion with excellent selectivity to 2-cyclohexene-1-one. The synthesized catalysts were characterized by various physiochemical techniques namely, powder XRD, N-2 physisorption, Raman spectroscopy, UV-Vis DRS, FTIR spectroscopy, XPS, FE-SEM, and HR-TEM. As revealed by various characterization results, the 1 wt% Co3O4/SiO2 catalyst shows better catalytic performance due to a more specific surface area and a high dispersion of Co3O4 nanoparticles on the SiO2 surface. Various reaction parameters like temperature, reaction time, amount of catalyst, oxidant, and solvent were also studied to optimize the reaction conditions. Further, the reusability of the catalyst was also tested up to five cycles and found to be stable with a negligible variation in the activity.