Abstract
The evolution of the adsorption and structural properties of large-pore SBA-16 silica samples was studied in relation to hydrothermal treatment and template removal procedures. These samples were synthesized using the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer Pluronic F127 as the structure-directing agent and tetraethyl orthosilicate as the silica source in the presence of hydrochloric acid (low concentration) and sodium chloride under various hydrothermal treatment conditions. The concomitant use of the recently reported two-step template removal procedure, which combines solvent extraction and low-temperature calcination, afforded the SBA-16 samples with large pore volumes, high surface areas, uniform cages and uniform cage openings as demonstrated by nitrogen and argon adsorption isotherms measured at −196°C. Small-angle X-ray diffraction spectra confirmed the existence of the Im3m symmetry group (body-centred cubic pore structure) for the samples studied. The efficiency of the aforementioned template removal method was confirmed via thermogravimetric analysis.