Structure and spectra of photochemically obtained nanosized silver particles in presence of modified porous silica

Abstract

Mesoporous silica powders and films modified with organic sensitizer benzophenone were used as photocatalysts in the reaction of silver ion reduction by isopropyl alcohol under UV-irradiation withλ=253.7 nm and 365 nm in presence of colloidal silica as stabilizer. Morphological changes of silver colloids during irradiation were studied using transmission electron microscopy, and correlated to the absorption spectra.

Silver and gold nanoparticles in silica matrices: synthesis, properties, and application

“…The methods for the production of the nanoparticles of the individual metals and of the bimetallic nanoparticles are similar: photoreduction, chemical reduction in aqueous media in the presence of stabilizers (polymers, inverse micelles), thermal reduction [30,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90]. There is no doubt that the photochemical method for the reduction of nanoparticles and bimetallic nanoparticles from their ions is the most economical and energy-and time-saving in comparison with other methods [29][30][31]77].…”

“…Mesoporous silica films and powders modified with benzophenone were investigated as photocatalysts for the reduction of silver and gold ions in aqueous solution [28][29][30][31]. A DRSh-500 high-pressure mercury lamp with a UV 7-60 filter was used as light source with wavelength 365 nm.…”

Rationales Design dünner funktioneller Oxidfilme mit eingebetteten magnetischen oder plasmonischen Metallnanopartikeln

“…Nach der Mie-Theorie hängt das OPR-Bandmaximum gemäß Gleichung (1) vom Brechungsindex (n) des Mediums ab, wobei m e und e die Elektronenmasse und -ladung, e 0 die hochfrequente Dielektrizitätskonstante des Metalls und N e die Dichte der freien Elektronen auf den Metallnanopartikeln darstellen. [24] …”

Rational Design of Functional Oxide Thin Films with Embedded Magnetic or Plasmonic Metallic Nanoparticles

“…According to Mies theory, the SPR band maximum depends on the mediums refractive index (n), as described by Equation (1), where m e and e are the electrons mass and charge, e 0 is the high-frequency dielectric constant of the metal, and N e is the density of free electrons on the metal nanoparticles. [24] Figure 4 (2a) shows the variation of the normalized visible absorption spectra of the films obtained with varied composition of the feedstock of the oxide phase, while t oxide was kept constant at 20 min. The SPR, Figure 4 (2b), shows a linear increase with the fraction of titanium precursor in the CVD feedstock of the oxide phase.…”