Pt nanoparticles confined in hollow silica nanoreactors as highly efficient catalysts for semihydrogenations of alkynes at atmospheric H2 pressure.

Abstract

In this work, Pt nanoparticles encapsulated hollow porous silica nanoreactors (Pt@HPSNs) was synthesized in one-pot by a reverse microemulsion system, and they exhibit good catalytic efficiency and stability for semihydrogenations of alkynes. The key design concept is to form Pt hydroxide nanoparticles mixed poly(ethyleneimine) nano-aggregates in water droplets, which further functions as seeds for silica deposition and the void templates to form the central voids. The Pt@HPSNs illustrate a wide adaptability for semihydrogenations of a series of terminal alkynes to the corresponding alkenes at mild reaction conditions, and demonstrate high yields of styrene for semihydrogenation of phenylacetylene, showing good catalytic efficiency for hydrogenation of phenylacetylene to styrene at atmospheric H2 pressure. The enhanced catalytic performance of Pt@HPSNs are ascribed to their hollow porous nanostructures, where the confinement of Pt nanoparticles in voids increase the structural stability and the confinement effect may increase the collision of reactants and Pt, resulting in improved catalytic efficiency.