Silver quasi-nanoparticles: bridging the gap between clusters molecular-like and plasmonic nanoparticles
Résumé
Herein, we report a new strategy for preparing connected silver sub-nanoparticles with unique optical behavior via a selective photo-assisted electrochemical reduction of silver cations in FAU-type zeolite X (FAUX) cages. Bi 2+ /Bi 3+ doped zeolite nanoparticles (ZX-Bi) were prepared by one-pot hydrothermal synthesis and stabilized as colloidal water suspension. Silver nitrate-containing ZX-Bi suspension was subjected to UV irradiation resulting in the reduction of silver cations and generation of Ag &+ n clusters (Ag@ZX-Bi). The physicochemical characterization of the samples, using XRD, TG, N2 sorption, NMR, HRTEM-STEM, ICP, EDX and XPS analyses, provided comprehensive information on the textural and structural properties, the chemical compositions and the metal oxidation state of the samples. Their optical behaviors have been investigated using UV-visible and photoluminescence spectroscopies. The IR-operando analysis under visible-light revealed local heating of Ag@ZX-Bi up to 400K. The theoretical calculation of the absorption, scattering, and extinction cross-sections sabs, ssca and sext of different silver models performed in this study, was in agreement with the experimental data, elucidating the unique optical behavior of the silver particles. The set of analyses show that quasi-nanoparticles of Ag are formed from bridged Ag clusters (AgCLs) through zeolite channels closing for the first time the gap between clusters and plasmonic nanoparticles.
Domaines
Matériaux
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