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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Anatase TiO2 nanocrystals anchored at inside of SBA-15 mesopores and their optical behavior

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Author(s):
Araujo, M. M. ; Silva, L. K. R. ; Sczancoski, J. C. ; Orlandi, M. O. ; Longo, E. ; Santos, A. G. D. ; Sa, J. L. S. ; Santos, R. S. ; Luz, Jr., G. E. ; Cavalcante, L. S.
Total Authors: 10
Document type: Journal article
Source: Applied Surface Science; v. 389, p. 1137-1147, DEC 15 2016.
Web of Science Citations: 21
Abstract

In this paper, a new synthesis method was proposed to obtain anatase titanium oxide (TiO2) nanocrystals anchored into SBA-15 molecular sieve, as a matrix assigned by the in-situ anchoring (ISA) method. Pure SBA-15 and modified with TiO2 nanocrystals at different Si/Ti molar ratios (R = 75, 50, and 25) were structurally characterized by X-ray diffraction (XRD), Micro-Raman and Fourier Transform infrared (FTIR) spectroscopies. Specific surface area, pore volume and average pore diameter were estimated using both Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods, respectively. Morphological aspects of these samples were observed by means of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Optical properties were investigated by ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. XRD patterns, Micro-Raman and FT-IR spectra indicate the TiO2 nanocrystals crystallized in a tetragonal structure anchored into the SBA-15 mesopores. BET and BJH methods prove a large amount of TiO2 nanocrystals were anchored inside of SBA-15 mesopores due to increase in surface area and average pore size of SBA-15 matrix. FE-SEM and TEM images showed the pure SBA-15 has an elongated hexagon-shaped microstructure, and an average size of 7.34 nm for 2D hexagonal mesopores. Moreover, ISA method was able to avoid blocking of mesopores, in addition promotes a significant increasing the impregnation rate of anatase TiO2 nanocrystals in SBA-15 matrix. A growth mechanism was proposed in order to explain the stages involved in the formation of TiO2-SBA mesoporous. UV-vis spectra revealed a dependence of the optical band gap energy (E-gap) with the decreasing of Si/Ti molar ratios. (C) 2016 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/14004-5 - Investigation of the photoluminescence and photocatalytic properties of pure and Mn, Cu, and Zn-doped BaWO4 and BaMoO4 powders
Grantee:Júlio César Sczancoski
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC