Systematic investigation of the pore structure and surface properties of SBA-15 by water vapor physisorption

In order to establish a structure-property correlation in water vapor sorption, various sets of the ordered mesoporous silica SBA-15 with systematically varying properties were synthesized and characterized. General trends concerning the surface polarity, aging temperature during synthesis and micropore volume were observed. Calcining the materials with increasing temperatures of 300-800 degrees C decreases the performance in water vapor sorption which correlates mainly with the amount and type of silanol groups on the silica surface. Furthermore, the aging temperature during synthesis influences the water vapor sorption capacity of SBA-15 at low relative pressure. The best results in terms of an increased uptake of water over a broad range of relative pressure can be obtained for materials with high micropore volume and high surface polarity. They can be tailor-made by using a routine to remove the template, i.e., a combination of extraction with ethanol and subsequent calcination at 300 degrees C. (C) 2015 Elsevier Inc. All rights reserved.