Palladium nanoparticles confined in the nanocages of SBA-16: Enhanced recyclability for the aerobic oxidation of alcohols in water

Via modification of mesoporous cage-like material SBA-16 followed by adsorption of Pd(OAc)(2) and reduction with NaBH4, Pd nanoparticles with a uniform size distribution were successfully confined in the nanocages of SBA-16, leading to a new solid catalyst for the aerobic oxidation of alcohols. The solid catalyst was characterized with N-2 sorption, XRD, TEM, FT-IR and XPS. Such a catalyst showed a high activity for the oxidation of benzylic alcohols, 1-phenylethanol and allylic alcohols without the presence of bases under air or O-2 atmosphere in water even at room temperature. The selectivities for the corresponding aldehydes and ketones were more than 99% in all the cases investigated. The developed catalyst could be facilely recovered and reused twelve times without significant decreases in activity and selectivity. Its recyclability was much better than that of the catalyst derived from amorphous silica under the same conditions. (C) 2010 Elsevier B.V. All rights reserved.