Some insight on the structure/activity relationship of metal nanoparticles in Cu/SiO2 catalysts

Abstract

The activity of two Cu/SiO 2 catalysts prepared by the chemisorption hydrolysis technique has been tested in the hydrogenation reaction of 3-methyl-cyclohexanone. Both catalysts were found to be very active at 60 °C and 1 atm of H 2 . Characterization of the materials by FT-IR of adsorbed CO and TEM put in light the presence of well formed Cu cristallites. By assuming a cuboctahedral model we could show that the hydrogenation activity is linked to high coordination sites on the metal particle. A comparison is also reported with a sample prepared by ammonia evaporation that was found to be inactive in the hydrogenation reaction under the same experimental conditions. The activity of Cu/SiO 2 catalysts in the hydrogenation of 3-methyl-cyclohexanone was found to be linked to high coordination sites on the metal Cu particle, whereas acidic sites are represented by defective, low coordination sites.