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

Autor(es)

Mourao, Henrique A. J. L. ^[1] ; Avansi, Jr., Waldir ^[2] ; Oliveira, Juliano E. ^[3] ; Firmiano, Edney S. ^[1] ; Ribeiro, Caue ^[3]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Science of Advanced Materials; v. 5, n. 1, p. 71-85, JAN 2013.
• Citações Web of Science: 6

Resumo

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)

• Processo FAPESP: 08/58539-4 - Novos metodos para a sintese hidrotermica de nanoestruturas lamelares de oxidos de titanio.
• Beneficiário: Henrique Aparecido de Jesus Loures Mourão
• Modalidade de apoio: Bolsas no Brasil - Doutorado