Silver Nanoparticle Generators: Silicon Dioxide Microspheres

Abstract

A green and simple approach has been developed to synthesize un-coated Ag nanoparticles (AgNPs) in situ on the surface of thiol-group-functionalized silica dioxide microspheres (TSMs) in the aqueous solution. As soon as the Ag ions attach onto the surface of TSMs, nucleation and growth of AgNPs can spontaneously complete within one minute without other reducing agents or capping agents. The main reason is that the self-assembled silane-layer formed by mercaptosilane molecules could reduce the Ag formation energy, transport electrons efficiently, improve the nucleation density, and protect AgNPs against oxidation. Thus, the supported AgNPs show excellent chemical/photochemical stability in air and solution. Meanwhile, the size of as-prepared AgNPs could be controlled by tuning the concentration of Ag ions. This process provides a general route to generate bare AgNPs on the surface of silica dioxide in situ, which might be extended to other materials and is promising in developing novel methodologies for making supported noble metal NPs with desired structure and properties.

Enhanced Antibacterial Activity of Poly (dimethylsiloxane) Membranes by Incorporating SiO2 Microspheres Generated Silver Nanoparticles

“…When the SMs dropped on the vinyl groups modified PDMS, the thiol-vinyl click reaction took place with the formed thioether bonds and then SMs were immobilized on the surface of PDMS by covalent bonds, which could efficiently avoid the escape of SMs from the surface of PDMS. It should be noted that the embedded SMs could absorb Ag + ions, and reduced Ag + ions into Ag 0 with the thiol groups [26]. Within one minute, the nucleation and growth of AgNPs can spontaneously complete without other reducing or capping agents.…”

“…Thiol-terminated SMs (~1 μm) were synthesized by remodeled sol-gel process as a previously published method [26]. Briefly, 0.1 g MPTMS was mixed with 10 g water under vigorous stirring until MPTMS droplets completely disappeared, and then NH 4 OH was added to the mixture solution to adjust the pH to 11.…”

“…To overcome the challenge of loading the AgNPs antibacterial and anti-adhesive surface to PDMS, we designed the silica microspheres (SMs) with in-situ growth of AgNPs on their surface, and the size of the as-prepared AgNPs (~15 nm) could be controlled by tuning the concentration of Ag + ions in our recent report [26]. In this paper, these SMs were covalently bonded to the bulk PDMS and bare AgNPs would be spontaneously generated on the surface of the prepared SMs through the reduction process of Ag + by thiol groups.…”

Surfactant‐Free In Situ Synthesis of Sub‐5 nm Silver Nanoparticles Embedded Silica Sub‐Microspheres as Highly Efficient and Recyclable Catalysts

“…After modification with MPTMS, thiol groups were anchored on the surface of the sub‐microspheres, which further attracted Ag + ions and subsequently reduced them to Ag 0 . So AgNPs then started to grow on the surface of the sub‐microspheres …”

“…The cages showed very high catalytic activity and could be used for at least four times . In the previous paper, we synthesized silica microspheres (∼1 μm.d) to generate AgNPs with the average diameter ∼15 nm on their surface . Here we fabricated much smaller silica sub‐microspheres (∼150 nm.d) and Ag + ions attached on the surface could transform into ultrafine AgNPs (<5 nm.d) within 10 minutes without extra capping and reducing reagents.…”