Facile synthesis of hollow structured mesoporous silica nanoreactors with confined ultra-small Pd NPs for efficient hydrogenation reactions

Abstract

A facile method has been developed for the synthesis of hollow structured mesoporous silica nanoreactors with confined ultra-small metal nanoparticles through a one-pot sol–gel process in ethanol–water/ammonia medium. As examples, Pd nanoparticles protected with PVP [poly(N-vinyl-2-pyrrolidone)] or dendrimer [hydroxyl-terminated poly(amidoamine) (PAMAM)] molecules were successfully encapsulated, and the small particle size could be well maintained (< 2 nm). Such nanoreactors exhibited excellent catalytic activity towards nitrobenzene hydrogenation under 1 MPa H2 pressure at room temperature, which could also be stably recycled without deterioration on the activity. The efficient strategy might be adapted onto other nanostructures for catalysis applications.