Silver supported on hierarchically porous SiO2 and Co3O4 monoliths: Efficient heterogeneous catalyst for oxidation of cyclohexene

Abstract This study describes silver (Ag) nanoparticles supported on hierarchically porous SiO 2 and Co 3 O 4 monoliths and the use of these materials as heterogeneous catalysts for the oxidation of cyclohexene. Structural characterization of these materials was carried out by various techniques including scanning electron microscopy (SEM), N 2 adsorption, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Characterization results revealed that Ag nanoparticles were incorporated into hierarchically porous SiO 2 and Co 3 O 4 without significantly affecting the structures of the supports. The oxidation of cyclohexene was investigated for hierarchically porous Ag/SiO 2 and Ag/Co 3 O 4 monoliths and powdered forms of the catalysts using H 2 O 2 as oxidant. Detailed parameters including the effect of temperature, oxidant, catalyst loading, and substrate to oxidant ratio were thoroughly studied. The catalyst was found to be stable and could be reused several times without affecting its catalytic activity under the optimized reaction conditions.