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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.)

A Study of the Precursors and Photoactivity of Nanostructures of Ti Oxides Synthesized by the Alkaline Hydrothermal Method

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Author(s):
Mourao, Henrique A. J. L. [1] ; Avansi, Jr., Waldir [2] ; Oliveira, Juliano E. [3] ; Firmiano, Edney S. [1] ; Ribeiro, Caue [3]
Total Authors: 5
Affiliation:
[1] Univ Fed Sao Carlos UFSCar, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil
[2] UNESP Univ Estadual Paulista, Inst Quim, BR-14801907 Araraquara, SP - Brazil
[3] Embrapa Instrumentacao, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Science of Advanced Materials; v. 5, n. 1, p. 71-85, JAN 2013.
Web of Science Citations: 6
Abstract

The present study describes the synthesis, characterization and photocatalytic potential of Ti oxide nanostructures of various morphologies and crystalline phases that were synthesized from 4 different precursors by the alkaline hydrothermal method. The materials were characterized by mainly X-ray diffraction (XRD), Raman spectroscopy, scanning and transmission electron microscopy (SEM and TEM), thermogravimetric analysis (TGA) and X-ray absorption spectroscopy ((AS). Also, photocatalytic potential was assessed by rhodamine B photodegradation. The materials obtained from peroxytitanium complexes (PTCs) exhibited a strong dependence on the concentration of KOH ({[}KOH]) used for synthesis. The pre-formed sheets of the PTCs were critical to the formation of nanostructures such as nanoribbons, and they were also compatible with the rolling up process, which can be utilized to form structures such as nanorods, nanowires or nanotubes. In the rhodamine photodegradation tests, TiO2 anatase nanostructures with six-coordinated Ti were more effective than the titanate ones (five-coordinated), despite having a smaller surface area and fewer OH groups. The lower photoactivity of the titanates was attributed to the presence of five-coordinated titanium species (TiO5), which may act as electron hole recombination centers. Furthermore, the material with a mixture of TiO2/titanate was shown to be promising for photocatalytic applications. (AU)