Óxidos de zinco - cobalto nanoestruturados : síntese e caracterização

• Ano de defesa: 2012
• Autor(a) principal: Lima-Tenório, Michele Karoline
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Departamento de Química; Programa de Pós-Graduação em Química; UEM; Maringá, PR; Centro de Ciências Exatas
• Palavras-chave em Português: Nanotecnologia; Óxido de zinco nanoestruturado; Óxido de cobalto; Brasil.; Nanotechnology; Zinc oxide; Cobalt oxide; Brazil.; Ciências Exatas e da Terra; Química
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/3915

In this work, zinc oxide, cobalt oxide and zinc/cobalt oxides were synthesized by a modified sol-gel method, in order to study the morphology, structure and other properties of these materials. The samples were analyzed by FTIR, XRD, TEM, Raman scattering spectroscopy and UV-vis photoacoustic spectroscopy. The mean crystallite size was 25-34 nm, estimated by the Scherrer's equation. The FTIR spectra and XRD patterns allowed to detect structural changes occurring in the samples due to the addition of different amounts of cobalt in zinc oxide. It was observed that the method allowed the doping of ZnO wurtzite structure with until approximately 30 mol% of cobalt. The UV-Vis photoacoustic spectra showed a decrease in the band gap energy from 2.99 eV (ZnO) to 1.68 eV (sample containing 30 mol% cobalt). It was attributed to imperfections and defects caused by the addition of dopant atoms, as evidenced by Raman scattering spectroscopy.