TY - JOUR

T1 - Structure-stabilizing silanols in amorphous silica with ultra-high specific surface area

AU - Евров, Даниил

AU - Курдюков, Дмитрий

AU - Нечитайлов, Андрей

AU - Краснова, Анна

AU - Мазур, Антон Станиславович

AU - Стовпяга, Екатерина

PY - 2025/11/20

Y1 - 2025/11/20

N2 - Submicron micro-mesoporous spherical silica particles are synthesized. The particles have the form of a sheet of highly hydroxylated silicon-oxygen tetrahedra crumpled into sphere. The structure determines outstanding porosity characteristics of the material synthesized, namely, extremely high specific surface area (SSA) up to ∼2300 m2/g and the pore volume of 0.86 cm3/g. The obtained SSA value is almost twice as high as that of previously reported for silica-based materials. A comprehensive study of the particles by thermogravimetric analysis and solid-state nuclear magnetic resonance spectroscopy revealed the concentration of surface hydroxyl groups of 3.5 OH/nm2 or 11 mmol/g. It is found that surface hydroxyl groups present predominantly in the form of single silanols, which form an H-bonded network and stabilize a delicate silica framework. It is shown that all Si-OH groups are external surface silanols accessible for reaction and/or interaction largely determining the functionality of the material. The hydrothermal stability of the synthesized material is demonstrated. The experiments on vapor-phase adsorption of different substances of various polarity (water, toluene, formic acid) revealed superior sorption capacity (at least two times higher) of the synthesized silica material compared to standard MCM-41-type silica and HY-zeolite. Compared to HY-zeolite sorption of toluene turned out to be even five times higher, which is due to the size of adsorbate molecule. Thus, the obtained silica with improved adsorption properties and a large number of active sites is highly promising for various sensors, separators, catalysts support.

AB - Submicron micro-mesoporous spherical silica particles are synthesized. The particles have the form of a sheet of highly hydroxylated silicon-oxygen tetrahedra crumpled into sphere. The structure determines outstanding porosity characteristics of the material synthesized, namely, extremely high specific surface area (SSA) up to ∼2300 m2/g and the pore volume of 0.86 cm3/g. The obtained SSA value is almost twice as high as that of previously reported for silica-based materials. A comprehensive study of the particles by thermogravimetric analysis and solid-state nuclear magnetic resonance spectroscopy revealed the concentration of surface hydroxyl groups of 3.5 OH/nm2 or 11 mmol/g. It is found that surface hydroxyl groups present predominantly in the form of single silanols, which form an H-bonded network and stabilize a delicate silica framework. It is shown that all Si-OH groups are external surface silanols accessible for reaction and/or interaction largely determining the functionality of the material. The hydrothermal stability of the synthesized material is demonstrated. The experiments on vapor-phase adsorption of different substances of various polarity (water, toluene, formic acid) revealed superior sorption capacity (at least two times higher) of the synthesized silica material compared to standard MCM-41-type silica and HY-zeolite. Compared to HY-zeolite sorption of toluene turned out to be even five times higher, which is due to the size of adsorbate molecule. Thus, the obtained silica with improved adsorption properties and a large number of active sites is highly promising for various sensors, separators, catalysts support.

KW - Adsorption

KW - Micro-mesoporous silica

KW - Silanols

KW - Spherical nanoparticles

KW - Ultra-high specific surface area

UR - https://www.mendeley.com/catalogue/9f5a1e6d-26cb-3288-8966-0cbdd4154b13/

U2 - 10.1016/j.colsurfa.2025.137523

DO - 10.1016/j.colsurfa.2025.137523

M3 - Article

VL - 725

JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects

JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects

SN - 0927-7757

M1 - 137523

ER -