%0 Journal Article
%A Boulahya, Khalid
%A Khouchaf, Lahcen
%A Das, Partha Pratim
%A Nicolopoulos, Stavros
%A Kovács Kis, Viktória
%A Lábár, János L.
%T Study of the Microstructure of Amorphous Silica Nanostructures Using High-Resolution Electron Microscopy, Electron Energy Loss Spectroscopy, X-ray Powder Diffraction, and Electron Pair Distribution Function
%D 2020
%U https://hdl.handle.net/20.500.14352/124552
%X Silica has many industrial (i.e., glass formers) and scientific applications. The understandingand prediction of the interesting properties of such materials are dependent on the knowledge ofdetailed atomic structures. In this work, amorphous silica subjected to an accelerated alkali silicareaction (ASR) was recorded at different time intervals so as to follow the evolution of the structureby means of high-resolution transmission electron microscopy (HRTEM), electron energy lossspectroscopy (EELS), and electron pair distribution function (e-PDF), combined with X-ray powderdiffraction (XRPD). An increase in the size of the amorphous silica nanostructures and nanoporeswas observed by HRTEM, which was accompanied by the possible formation of Si–OH surfacespecies. All of the studied samples were found to be amorphous, as observed by HRTEM, a factthat was also confirmed by XRPD and e-PDF analysis. A broad diffuse peak observed in the XRPDpattern showed a shift toward higher angles following the higher reaction times of the ASR-treatedmaterial. A comparison of the EELS spectra revealed varying spectral features in the peak edges withdifferent reaction times due to the interaction evolution between oxygen and the silicon and OH ions.Solid-state nuclear magnetic resonance (NMR) was also used to elucidate the silica nanostructures.
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