abstract
Mesoporous titania-silica (TiO(2)-SiO(2)) composites have been directly synthesized through a hydrothermal method in weak acidic conditions by using TiCl(3) solution as a titanium source and triblock copolymer P123 (EO20PO70EO20) as a template with the assistance of zinc acetate. Characterizations by XRD, TEM, and N(2) sorption measurements show that highly ordered mesostructured TiO(2)-SiO(2) with the BET specific area of 882 m(2)/g was obtained with the Ti/Si molar ratio of 0.1. Morphology of the composites can be controlled by the incorporation of different amounts of titanium species. Highly curved shapes such as winding, wormlike, and wheat grain-like particles were obtained by this direct synthetic method. Acidity and zinc acetate concentration can also affect the morphology of the composites. UV-vis, FTIR and (29)Si MAS NMR results display that titanium species exist both in the framework and extra-framework of the mesoporous SiO(2). Wide angle XRD, Raman, and HRSEM results show that the outer surface of the SiO(2) (probably Ti-doped) is decorated by round anatase nanocrystallites (probably Si-doped), whereas X-ray mapping results reveal that titanium species are highly dispersed on the final mesoporous composites. The formation mechanism of the mesophase was discussed based on characterization results. Photocatalytic results show that the TiO(2)-SiO(2) composites prepared in this way have high catalytic activity in the photodegradation of isopropanol due to both framework and surface titanium species.
keywords
MOLECULAR-SIEVE SBA-15; PORE-SIZE ANALYSIS; HIGH TI CONTENT; SUBSTITUTED SBA-15; PHOTOCATALYTIC PROPERTIES; MESOSTRUCTURED SILICA; CATIONIC SURFACTANT; CATALYTIC-ACTIVITY; ANATASE TIO2; COPOLYMER
subject category
Chemistry; Science & Technology - Other Topics; Materials Science
authors
Wu, ZY; Tao, YF; Lin, Z; Liu, L; Fan, XX; Wang, Y
our authors
Zhi Lin
Principal Researcheracknowledgements
We greatly appreciate the financial support from FCT, POC12010, PTDC, FSE, and FEDER. We also thank Marta Ferro, Marc-Georg Willinger, and Augusto Lopes of CICECO for the help of acquisition of TEM and SEM images.