One-step preparation of silver nanoparticles confined in functionalized-free SBA-15 channels

Supported Ag nanoparticles were successfully prepared by a one-step in situ procedure within channels of SBA-15 mesoporous silica. The reaction was carried out in N,N-dimethylformamide (DMF) at 25 °C with no need for silica surface functionalization or demanding time-consuming steps, and presents important advantages over the usual method. The small-angle X-ray scattering (SAXS) pattern of SBA-15 presents well-defined reflections associated with P6mm hexagonal symmetry. TEM micrographs of supported Ag nanoparticles (SBA-15/Ag) clearly show the presence of spheroidal and elongated Ag nanoparticles that are confirmed by surface plasmon resonance band in the UV–vis absorption spectrum. No evidence of Ag nanoparticle agglomeration was observed throughout the inorganic matrix. Ag nanoparticle formation within channels of SBA-15 decreases its specific surface area and total pore volume, as evidenced by nitrogen adsorption–desorption isotherms, with no damage to the silica framework. The method shows itself to be very efficient, fast and convenient for the synthesis of supported Ag nanoparticles in SBA-15 channels.