矿床地球化学国家重点实验室知识库

Puzzling aspects of the microporous structure of Stober silica, including inconsistencies in the BET specific surface area and the long measurement time required for N-2 adsorption, hinder further research on and potential applications of this material. In this work, Stober silica samples prepared using systematic and detailed post-treatment methods were characterized by N-2 adsorption, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, elemental analysis, and Fourier transform infrared spectroscopy. We have found that the often overlooked sample preparation conditions may be the main causes that perplex the gas adsorption characterization results of Stober silica samples. The pore-blocking processes associated with a variety of sample treatment methods are discussed in detail. Strong evidence for the particle growth model and pore-blocking mechanism involving ethoxyl groups, Si species, and condensation of silanols is provided. A remarkable result is that the measurement time is shortened from 1 month in our previous work to 2-3 days for samples with large specific surface areas. A suitable post-treatment condition is recommended to obtain microporous Stober silica with a short measurement time, including water washing, low temperature drying without a vacuum, and a short storage time.