Synthesis of silicate sol–gel matrix embedded silver nanostructures: Efficient nanocatalyst for the reduction of 4-nitrophenol

Amine functionalized silicate sol–gel matrix embedded silver nanoparticles (Ag NPs) were prepared in the presence of β-cyclodextrin (β-CD–Ag–TPDT NPs) by a single-step process. The formation of sub-10 nm tetra twinned Ag nanostructures was confirmed by high resolution transmission electron microscopy studies. The reduction of 4-nitrophenol by NaBH4 was used as a model to study the catalytic efficiency of the as prepared Ag nanostructures. The 4-nitrophenol forms an inclusion complex with the hydrophobic β-CD cavity because of the strong affinity of β-CD to the phenyl ring moieties. The catalytic reduction of 4-nitrophenol included in the β-CD cavity by NaBH4 was monitored in the presence of the Ag NPs using the absorption spectrophotometer by the kinetic mode analysis. The catalytic performance of the β-CD–Ag–TPDT NPs was greatly enhanced towards the 4-nitrophenol reduction reaction. The tetra twinned shaped β-CD–Ag–TPDT NPs with the size of sub-10 nm showed higher catalytic activity than the β-CD–Ag NPs and Ag–TPDT NPs.

► The single-step synthesis of size-controlled Ag NPs embedded in functionalized amine silicate sol–gel matrix is reported.
► The formation of tetra-twinned Ag NPs is observed in silicate sol–gel matrix.
► The efficient catalytic reduction of 4-nitrophenol in the presence of Ag NPs is observed.