Loading...
Search for:
silica-matrix
0.006 seconds
Lipase immobilisation on magnetic silica nanocomposite particles: Effects of the silica structure on properties of the immobilised enzyme
, Article Journal of Materials Chemistry ; Volume 22, Issue 17 , 2012 , Pages 8385-8393 ; 09599428 (ISSN) ; Kazemeini, M ; Tabandeh, F ; Arpanaei, A ; Sharif University of Technology
2012
Abstract
Uniformly sized superparamagnetic single-shell nonporous (S1) and double-shell mesoporous silica nanocomposite particles with ∼130 nm magnetite cluster cores are synthesised in this study. Mesoporous particles are prepared with two BJH pore sizes (2.44 and 3.76 nm, designated as S2 and S3 particles, respectively). Once the lipase was immobilised on particles, our results showed that the enzyme loading capacities of mesoporous structures, i.e. S2 and S3, are higher than that for nonporous particles (S1). Hydrolytic activity tests reveal that immobilised lipases retain about 90% of the free enzyme's activity. Furthermore, comparing to the free enzyme, the thermal stability of immobilised...
Effect of silica encapsulation on the stability and photoluminescence emission of FAPbI3 nanocrystals for white-light-emitting perovskite diodes
, Article Journal of Alloys and Compounds ; Volume 907 , 2022 ; 09258388 (ISSN) ; Mohammadi, M ; Tabatabaei Rezaei, N ; Aynehband, S ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The α-FAPbI3 perovskite nanocrystals exhibit interesting optical properties, which make them attractive for versatile optoelectronic applications; however, the spontaneous phase transformation to the non-perovskite phase (δ-FAPbI3) in humid conditions requires a new strategy to improve the phase stability of the material. We employed 3-Aminopropyl triethoxysilane (APTES)-assisted reprecipitation and sol-gel methods at ambient temperature to prepare stable α-FAPbI3 nanocrystals embedded in a silica matrix. Transmission electron microscopy (TEM) and X-ray diffraction analysis determined that ultrafine perovskite nanocrystals (11.5 ± 3 nm) were uniformly distributed in a silica matrix....
Chemical durability of metallic copper nanoparticles in silica thin films synthesized by sol-gel
, Article Journal of Physics D: Applied Physics ; Volume 41, Issue 23 , November , 2008 ; 00223727 (ISSN) ; Sharif University of Technology
2008
Abstract
In this study, chemical durability of metallic copper nanoparticles dispersed in sol-gel silica thin films was investigated by exposing the films to air after a reduction process. At first, heat treatment in air for 1 h produced silica films containing crystalline cupric oxide nanoparticles agglomerated on the film surface. Subsequently, reduction of the oxidized films in a reducing environment of N2-H2 for another 1 h at temperatures of 400, 500 and 600 °C resulted in the formation of crystalline metallic Cu nanoparticles diffused in the silica matrix. The time evolution of the surface plasmon resonance absorption peak of the reduced Cu nanoparticles was studied after the reduction...