Pd nanoparticles embedded in the outershell of a mesoporous core–shell catalyst for phenol hydrogenation in pure water

A multi-component mesoporous core–shell structured nanocatalyst was prepared via encapsulation of a hydrophobic mesoporous carbon with amino-functionalized mesoporous silica, followed by coordination of palladium precursors and then reduction with a NaBH4 reagent. The resulting Pd/MCN@MS-NH2 catalyst could be well-dispersed in an aqueous medium owing to the inherent hydrophilic properties of the mesoporous silica shell. The experimental results indicated that the Pd/MCN@MS-NH2 catalyst had high catalytic activity and selectivity for the hydrogenation of phenol to cyclohexanone under 1 atm of H2 at 80 °C for 3 h in pure water (conversion > 99% and selectivity 99%). Furthermore, the catalyst can be easily recovered and reused six times without significant loss of catalytic activity.