Comparative study of texture and rheological properties of AgI-SiO2 hybrid powders with different pore structure

• Published in: Journal of sol-gel science and technology 2023-11, Vol.108 (2), p.339-351
• Main Authors: Averkina, A. S., Kondrashova, N. B., Saenko, E. V., Shamsutdinov, A. Sh, Valtsifer, V. A., Stopar, D.
• Format: Article
• Language: English
• Subjects: Aggregates; Angle of repose; Ceramics; Chemistry and Materials Science; Comparative studies; Composites; Crystallites; Glass; Inorganic Chemistry; Low temperature; Materials Science; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Sol-gel and hybrid materials with surface modification for applications; Rheological properties; Rheology; Silicon dioxide; Silver; Specific surface; Surface area
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-023-06086-x

AgI-SiO 2 hybrid powders (HPs) based on SBA-15, MCM-41, and MCM-48 have been prepared by template co-condensation of silica and silver iodide under hydrothermal conditions. The effect of the [Ag]/[Si] ratio and the type of silica matrix on the textural, structural, morphological, and rheological properties of the HPs has been studied. The formation of the target phase of iodargyrite (β-AgI) is dependent both on the ratio of the main components [Ag]/[Si] and on the pore arrangement in the silica matrix, as detected by XRD. The small-angle XRD and low-temperature nitrogen adsorption data have shown the textural and structural properties of AgI-SiO 2 hybrid powders to be similar to the porous structure of the initial silica matrices—SBA-15, MCM-41, or MCM-48. A uniform distribution of silver iodide in all silica matrices, SBA-15, MCM-41 and MCM-48, has been demonstrated by energy dispersive microanalysis (EDAX). For AgI-SiO 2 powders with various types of pore arrangement, a high fluidity degree has been demonstrated using the data on the natural angle of repose. It has been shown that MCM-48 based β-AgI-SiO 2 powders are characterized by the smallest crystallite sizes (~6 nm), and average size of particles (50 nm) and average size of particle aggregates (13 μm), the highest specific surface area (up to 860 m 2 /g) and the best fluidity. Graphical Abstract Highlights The formation of the target β-AgI phase, iodargyrite, in AgI-SiO 2 hybrid powders (HP) depends both on the component [Ag]/[Si] ratio and on the pore arrangement type of the silica matrix. Crystal phase, corresponding to iodargyrite, was detected in HPs samples prepared using the [Ag]/[Si] ratios within the range from 0.04 to 0.08. In AgI-SiO 2 powders prepared by hydrothermal template synthesis via а co-condensation route, the ordered pore arrangement was found to be similar to that of the initial silica matrices—SBA-15, MCM-41 or MCM-48. The smallest crystallites (~6 nm), average size of particles (50 nm) and average size of particle aggregates (13 μm), the highest specific surface area (up to 860 m 2 /g), and the best fluidity was found in the case of β-AgI-SiO 2 powders based on the MCM-48 matrix.