Silver nanoparticles immobilized on fibrous nano-silica as highly efficient and recyclable heterogeneous catalyst for reduction of 4-nitrophenol and 2-nitroaniline

Abstract In this study, a novel fibrous nano-silica (KCC-1) based nanocatalyst (Ag/KCC-1) with high surface area and easy accessibility of active sites was successfully developed by a facile approach. KCC-1 with high surface area was functionalized with amino groups acting as the robust anchors so that the silver nanoparticles (Ag NPs) with average diameter of about 4 nm were well-dispersed on the fibers of the KCC-1 microspheres, without aggregation. The synthesized Ag/KCC-1 nanocatalyst exhibited excellent catalytic activity for the reduction of 4-nitrophenol and 2-nitroaniline using sodium borohydride (NaBH 4 ) in water at room temperature owing to the easy accessibility of the active sites. Importantly, the Ag/KCC-1 nanocatalyst was easily recovered and reused for at least ten cycles in both the reduction reactions; thus, confirming its good stability. The enhanced stability was attributed to the modification of the fibrous nature of KCC-1 by the amino groups; thus, restricting Ostwald ripening and leaching of Ag NPs. Therefore, the abovementioned approach based on fibrous KCC-1 provided a useful platform for the fabrication of noble metal nanocatalysts with easy accessibility, which would be highly efficient in various catalytic reductions.