Silver-controlled evolution of morphological, structural, and optical properties of three-dimensional hierarchical WO3 structures synthesized from hydrothermal method

Autor(es)

Lopes, L. F. ^[1] ; Pontes, F. M. ^[1] ; Garcia, L. O. ^[1] ; Pontes, D. S. L. ^[1] ; Padovani, D. ^[1] ; Chiquito, A. J. ^[2] ; Teixeira, S. R. ^[3] ; Colmenares, Y. N. ^[4] ; Mastelaro, V. R. ^[4] ; Longo, E. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, UNESP, Dept Chem, POB 47, BR-17033360 Bauru, SP - Brazil

^[2] Univ Fed Sao Carlos, NanO LaB, Dept Phys, Via Washington Luiz, Km 235, POB 676, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Estadual Paulista, FCT, Dept Phys, Rua Roberto Simonsen 305, BR-19060900 Presidente Prudente, SP - Brazil

^[4] Univ Sao Paulo, Phys Inst Sao Carlos IFSC, Sao Carlos, SP - Brazil

^[5] Univ Fed Sao Carlos, Dept Chem, CDMF, LIEC, Via Washington Luiz, Km 235, POB 676, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 736, p. 143-151, MAR 5 2018.
• Citações Web of Science: 5

Resumo

Hierarchical structures of self-assembled three-dimensional (3D) WO3-Ag were synthesized via hydrothermal growth using precursor solutions of peroxopolytungstic acid with different amounts of Ag. The as-grown samples were analyzed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The XRD and Raman studies showed that as the amount of Ag was varied from 0 to 10 wt% in the hydrothermal growth solution, the crystal phase gradually changed from orthorhombic WO3 center dot 0.33H(2)O to hexagonal WO3. The FTIR and TGA studies revealed different hydration levels, supporting the XRD and Raman results. By controlling the amount of Ag in the precursor solution, platelet-like building blocks and hexagonal building blocks were obtained, highlighting the role of Ag in the hydrothermal growth of 3D WO3 center dot 0.33H(2)O and WO3 microcrystals. In addition, high-magnification FESEM images showed that the Ag nanoparticles were anchored on the surface of the 3D hierarchical WO3-Ag structures, and the UV-vis measurements demonstrated that the 3D hierarchical structures gradually absorbed more light when the Ag content was increased. Moreover, the band-gap energy decreased when the Ag content was increased from 0 wt% (Eg = 2.65 eV) to 10 wt% (Eg = 2.26 eV). These experimental results demonstrate that the amount of Ag played a crucial role in determining the building blocks' morphology, and the hydration level, optical properties, and crystal phase of the WO3 center dot nH(2)O microcrystals. (C) 2017 Published by Elsevier B.V. (AU)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 12/14106-2 - Designe de óxidos multifuncionais com arquitetura perovskite (Pb,Sr,La, Bi) (Ti,Fe) O3
• Beneficiário: Fenelon Martinho Lima Pontes
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/20536-7 - Materiais Ferroelétricos Multifuncionais: Estudos das Propriedades Ópticas, Elétricas e Fotoluminescente.
• Beneficiário: Debora da Silva Lima Pontes
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado