Yolk–shell nanospheres with soluble amino-polystyrene as a reservoir for Pd NPs

Abstract

The fabrication of silica/polymer composites with high polymer content, high stability and unique nanostructures still remains a difficult task though they have wide potential applications in the field of sensing, catalysis, bio-imaging and so on. Herein, the synthesis of yolk–shell nanospheres with soluble amino-polystyrene as a core material (PS-NH₂@mesoSiO₂ YSNs) have been reported, which is achieved by successive nitration and reduction of polystyrene nanospheres (PS) confined in silica hollow shells. Both the thermal stability and anti-swelling ability of PS-NH₂ in the core of yolk–shell nanospheres are greatly enhanced due to the confinement effect. PS-NH₂@mesoSiO₂ could be used as a reservoir for stabilizing Pd NPs. PS-NH₂@mesoSiO₂ YSNs with high amino content have high anti-swelling ability and result in Pd NPs with small particle size and high stability. Pd/PS-NH₂@mesoSiO₂ is an efficient catalyst for the selective hydrogenation of acetophenone (AP) to produce α-phenyl ethanol (PE). NH₂ groups in the core of PS-NH₂@mesoSiO₂ yolk–shell nanospheres not only stabilize Pd nanoparticles but also provide basic surroundings for suppressing the hydrogenolytic splitting of the C–OH to improve the selectivity for α-phenyl ethanol.