Synthesis and Characterization of Anatase and Anatase/SBA-15

OSCAR ANUNZIATA; MARÍA MARTÍNEZ; MARCOS GÓMEZ; ANDREA BELTRAMONE

Buenos Aires, Argentina

Simposio; 15th International Symposium on Metastable, Amorphous and Nanostructured Materials (ISMANAM 2008); 2008

UBA

Titanium dioxide (TiO2), as anatase phase (A), highly crystalline and a compositeanatase/SBA-15 were synthesized by a novel method. BET, XRD, SEM, TEM, FTIR,RAMAN and UV-Vis studies were made. The incorporation of TiO2 to SBA-15 prevents thetransformation of A to rutile phase (R), and completely limits the growth of cluster of TiO2non-blocking of pores SBA-15. The air calcination of composites up to 800ºC, slightlyincreased the size of A crystals from 5.0 to 7.5 nm, unlike single TiO2, indicating that thesecrystals within the mesostructure, have relatively high thermal stability. The developedmethods were effective for the synthesis as much of A like of composite. Recently, we reportour first results of the development of SBA-3, SBA-15, Al-SBA-15 and SBA-1 by newsroutes. In the same way Li Zhao and Jiaguo Yu, report the highly dispersed TiO2nanoparticles using SBA-15 as hard template, employing a conventional method to prepareSBA-15 and TiO2. The present work reports a new method of synthesis for the obtaining ofTiO2 (A) highly crystalline and a composite TiO2/SBA-15. Figure 1, shows the XRD of thecomposite, TiO2/SBA-15 heated at high treatments as 800ºC; the only phase is A, whereasreaching to 900ºC, a mixture of A/R in the composite was found. UV-Vis of the samplesindicate clearly that, there is a shift to the blue (fig. 2), in the absorption band for A within thehost, respect to A (380 nm for A pure), which implies a smaller size of the crystal of A/SBA-15. This result strongly suggests that SBA-15, acts like a nanoreactor, suppressing witheffectiveness the growth of the TiO2 particles, in correspondence with the rest of the results ofcharacterization before showed. A/SBA-15 image of TEM (fig. 3), shows the pores (clearzones) and so large similar of wall (darker zones) described for SBA-15.