Modification of micropore-containing SBA-3 by TEOS liquid phase deposition

SBA-3 with pore sizes of 22-25 Å has been successfully prepared by TEOS liquid phase deposition on the pristine SBA-3 with a pore size of ca. 27 Å. After the first TEOS modification, the resulting sample (Name: M1/SBA-3) shows obvious changes in textural properties. As compared to SBA-3, M1/SBA-3 has negligible micropores, its BET surface area and pore volume decrease by 24% and 40% respectively, its wall thickness increases from 15 Å to 22 Å and its pore size decreases from 27 Å to 23 Å. The presence of ethoxysilyl groups on M1/SBA-3 is supported by FTIR and carbon content measurement, and their loading amount is estimated to be ca. 5.7 wt% by TGA. The second TEOS modification is less efficient to change the textural properties of SBA-3 owing to its lower loading (ca. 1.3 wt%).