Multiple Silver Nanoparticles Anchored Hollow Mesoporous Silica Nanospheres by Polyacrylic Acid Aggregate Templating Approach for Catalytic Reduction of p-Nitrophenol.

Anchoring metal cores inside porous shells can endow metal catalyst with high selectivity and stability. Herein, multiple silver nanoparticles were successfully anchored in hollow mesoporous silica nanospheres (Ag@HMSNs) through a facile one-pot method. Polyacrylic acid aggregates self-assembled in water/ethanol solvent were used as core templates and Ag nanoparticles captors, and hexadecyl trimethoxysilane (C16TMS) was used as the pore-making agent. The hollow cavity, encapsulated multiple Ag nanoparticles, and mesoporous silica shell of the Ag@HMSNs were confirmed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and nitrogen sorption analysis. Just as expected, Ag nanoparticles (2-5 nm) were encapsulated in the cavity of hollow mesoporous silica nanospheres with the size of about 200 nm. The fabricated Ag@HMSNs showed excellent performance for catalytic reduction of p-nitrophenol (4-NP). Also, catalytic activity of the Ag@HMSNs for 4-NP reduction was increased with the addition amount of the pore-making agents and surface areas. The superior catalytic performance was attributed to the unique structural features of Ag@HMSNs architecture, in which the mesoporous shell provided readily accessible pathway for fast transport of reactants to the encapsulated Ag nanoparticles.

Facile fabrication of silver nanoparticles deposited cellulose microfiber nanocomposites for catalytic application.

In this study, we have prepared silver nanoparticles deposited cellulose microfibers (Ag-CMFs) with excellent catalytic property. The cellulose microfibers with a mean diameter of approximately 270 nm are regenerated by deacetylation of cellulose acetate microfibers. Silver nanoparticles are deposited onto the surface of the cellulose microfibers by a simple wet reduction of silver precursor using glucose as reducing agent. The morphology, thermal stability and catalytic activities of the samples have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and UV-vis spectrophotometer. The average size of Ag nanoparticles deposited on the fibers is approximately 10 ±â€¯5 nm, and the deposition of the Ag nanoparticles does not change the morphology of the cellulose microfibers. The obtained Ag-CMFs exhibit excellent catalytic activity and reusable character for the reduction of p-nitrophenol by sodium borohydride. Therefore, the Ag-CMFs prepared by the facile method is expected to be an effective and promising catalytic material.