Hydrothermal syntheses of large porous SBA-16-like mesostructures were obtained, considering the effect of several secondary structure directing agents (P123, NaCl, CTMABr and butanol), on the gels containing F127 in acidic solution, with TEOS as the only silica source. These new synthesized materials have their texture and structure clearly affected by the proposed additions of these agents. The degrees of silica condensation increased from 1.68 to 2.26, as observed by solid state 29Si NMR. Characterization by SAXS, TEM and nitrogen sorption at 77K revealed a decrease in pore volume from 1.7 to 0.4cm3g-1 for the sample synthesized with NaCl, while the wall thickness decreased from 10.2 to 8.1nm when CTMABr was used as secondary structuring agent. The morphologies observed for all samples were distinct, varying from plate-like until spherical and dodecahedral forms. Some morphological features were well correlated with other data, such as pore volume and surface area, measurements that have contributions from intraparticular pores. © 2012 Elsevier B.V.
Almeida R.K.S., Pires C.T.G.V.M.T., Airoldi C. (2012). The influence of secondary structure directing agents on the formation of mesoporous SBA-16 silicas. CHEMICAL ENGINEERING JOURNAL, 203, 36-42 [10.1016/j.cej.2012.06.114].
The influence of secondary structure directing agents on the formation of mesoporous SBA-16 silicas
Pires C. T. G. V. M. T.;
2012
Abstract
Hydrothermal syntheses of large porous SBA-16-like mesostructures were obtained, considering the effect of several secondary structure directing agents (P123, NaCl, CTMABr and butanol), on the gels containing F127 in acidic solution, with TEOS as the only silica source. These new synthesized materials have their texture and structure clearly affected by the proposed additions of these agents. The degrees of silica condensation increased from 1.68 to 2.26, as observed by solid state 29Si NMR. Characterization by SAXS, TEM and nitrogen sorption at 77K revealed a decrease in pore volume from 1.7 to 0.4cm3g-1 for the sample synthesized with NaCl, while the wall thickness decreased from 10.2 to 8.1nm when CTMABr was used as secondary structuring agent. The morphologies observed for all samples were distinct, varying from plate-like until spherical and dodecahedral forms. Some morphological features were well correlated with other data, such as pore volume and surface area, measurements that have contributions from intraparticular pores. © 2012 Elsevier B.V.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
