کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
74152 | 49082 | 2012 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Effect of silver encapsulation on the local structure of titanosilicate ETS-10 Effect of silver encapsulation on the local structure of titanosilicate ETS-10](/preview/png/74152.png)
Silver(0) nanoparticles stabilized by titanosilicate (ETS-10) framework were synthesized by following a simple two step procedure involving the incorporation of silver(I) (Ag+) ions into ETS-10 matrix via ion-exchange with extra framework Na+ and K+ cations followed by their reduction with sodium borohydride (NaBH4) in aqueous medium all at room temperature. Silver(0) nanoparticles dispersed in the ETS-10 matrix were collected as gray powders and characterized by using advanced analytical methods including ICP-OES, P-XRD, XPS, FE-SEM, TEM, HR-TEM, DR-UV–vis, Raman spectroscopies and N2 adsorption–desorption technique. Overall result shows the formation of silver(0) nanoparticles dispersed within the framework of ETS-10 without causing alteration in ETS-10 lattice and mesopore formation. The changes in the local titanate (TiO32−) structure of ETS-10 resulting from the incorporation of silver(I) ions and formation of silver(0) nanoparticles within the titanosilicate (xTiO2 (1 − x)SiO2) framework were extensively studied on silver(I)-exchanged and silver(0) nanoparticles containing samples, separately. Although maintaining of structural integrity of host material had been monitored for silver(I)-ETS-10, detailed Raman analyses of silver(0)-ETS-10 samples showed significant changes in the titanate quantum wires of ETS-10 framework depending on the silver loading. Total collapse of these units was observed in the silver(0)-ETS-10 samples with high silver loading (15 wt.% silver(I)). Moreover, the catalytic application of silver(0)-ETS-10 was demonstrated in the aerobic oxidation of diphenyl carbinol to benzophenone, which showed that silver(0)-ETS-10 is a highly active and selective catalyst in this reaction. Additionally, they were found to be highly stable catalyst for this transformation.
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► Local structural changes in ETS-10 upon incorporating silver nanoparticles.
► Silver nanoparticles were formed within the ETS-10 matrix by chemical reduction.
► Destruction of the titanate wire increases with the increasing silver loading.
Journal: Microporous and Mesoporous Materials - Volume 159, 1 September 2012, Pages 1–8