A simple method to ameliorate hierarchical porous structures of SiO2 xerogels through adjusting water contents

- Micro-/meso-porous SiO2 xerogels were fabricated with low concentration of water.
- Physicochemical properties and porous structure of the SiO2 xerogels were evaluated.
- Formation mechanism of the micro-/meso-porous SiO2 xerogels was elaborated.

In this contribution, hierarchical micro-/meso-porous SiO2 xerogels were successfully prepared through a Stöber methodology coupled with following drying process. The SiO2 xerogels were consisted of nanoparticles of 20-40 nm in size with different contents of water. Fourier transform infrared spectroscopy proved that SiOC2H5 and SiOH groups could be formed in SiO2 xerogels. Further analyses declared that the amount of the SiOC2H5 groups decreased while the concentration of SiOH was firstly increased and then suffered a decline with improving contents of water. Besides, the SiO2 xerogels was endowed with controllable micro-/meso-porous structure. Furthermore, the formation mechanism of the micro-/meso-porous SiO2 xerogels was tentatively put forward. As a consequence, SiO2 xerogels with controllable hierarchical micro-/meso-porous structure could act as the smart material for huge development in catalytic fields.

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