Amino-functionalized silicananoparticles with center-radially hierarchical mesopores as ideal catalyst carriers

Abstract

Our previously fabricated amino-functionalized silica nanoparticles (NPs) with center-radially hierarchical mesopores (NH₂-HMSNs) were purified by a filtration membrane and used as catalyst carriers in the current article. Noble metal NPs (Au, Pd, Pt and Au & Pt) with small sizes (3–8 nm) were successfully immobilized into the NH₂-HMSNs via the deposition–precipitation method. These noble metal NPs with readily adjusted small sizes have high density and well-dispersed distribution on the surface of large mesopores of NH₂-HMSNs. Among them, Au–NH₂-HMSNs were investigated as the composite catalyst in the catalytic reduction of 2-nitroaniline (2-NA) as a model reaction and exhibited excellent catalytic activity and stability. The presence of center-radially large mesopores in the NH₂-HMSNs may favor the loading of noble metal NPs with high density and well-dispersed distribution on the surface of large mesopores of NH₂-HMSNs. Metal–NH₂-HMSNs may be more promising composite catalysts due to their superstructure of center-radially hierarchical mesopores that maybe significantly enhance and harmonize the diffusion of guest molecules of different sizes through the porous matrices.