Facile synthesis of pure silicon zeolite-confined silver nanoparticles and their catalytic activity for the reduction of 4-nitrophenol and methylene blue

Supported noble metal heterogeneous catalysts have been proven to be effective for the treatment of toxic organic pollutants. Herein, ultrafine Ag nanoparticles (NPs) with an average size of approximately 4.37 nm was decorated on the surface of pure silicon zeolite nanoparticle (PSZN) and confined in pore channels through a low-cost and environmentally friendly in-situ reduction strategy. The prepared Ag/PSZN nanocomposites showed ultrahigh catalytic activity for the reduction of 4-nitrophenol (4-NP) (∼200 s, 17.29 × 10-3 s−1) and methylene blue (MB) (∼4 min, 76.53 × 10-2 min−1), which outperforms the majority of the previously reported Ag-based catalysts. The excellent catalytic performance is due to the large loading amount (Wt = 16.8 %) and ultrasmall size of Ag NPs, which provides abundant active sites. Moreover, it showed outstanding recyclability of 93 % and 86 % removal of 4-NP and MB, respectively, after 10 cycle reactions, and stability after 300 days of storage at room temperature. This work offers new insights into the fabrication of Ag-based catalysts for efficiently removing organic pollutants from aqueous solutions.