Desenvolvimento de catalisadores a base de níquel com estrutura perovsquita para a utilização na produção de gás de síntese

• Ano de defesa: 2011
• Autor(a) principal: Santos, José Carlos dos
• Orientador(a): Souza, Anne Michelle Garrido Pedrosa de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Sergipe
• Programa de Pós-Graduação: Pós-Graduação em Química
• País: BR
• Palavras-chave em Português: Catalisadores perovsquitas LaNiO3; Gás de síntese; Oxidação parcial do metano; Métodos de síntese
• Palavras-chave em Inglês: LaNiO3 perovskite catalysts; Syngas; Partial oxidation of methane; Synthesis methods
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://ri.ufs.br/handle/riufs/6156

Nickel-based catalysts with perovskite like structure have shown promising application in several catalytic reactions such as in the partial oxidation of methane to obtain syngas (H2 + CO). However, these properties are potentially influenced by synthesis methods, calcinations conditions (temperature, time and atmosphere) and substitutions of sites A and/or B in the structure. The effects of these variables have been studied with the aim of improving the performance of catalysts in the production of syngas and to avoid deactivation resulting from coke deposition. In the present study, nickel-based catalysts (LaNiO3) with perovskite like structure were prepared by polymeric precursors, chelating precursors and gel modified proteic methods. All samples were subjected to thermal treatment and then calcined at 700 °C (for 1 or 2 h) to obtain the targed phase. LaNiO3 catalysts calcined at 700 °C with the lowest content of chelating agents were supported on alumina. The resulting ceramic powders were characterized by X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, specific surface area, scanning electron microscopy and temperature programmed reduction tests. XRD patterns of the powders calcined at 700 °C showed the formation of perovskite phase in all samples. The characteristic peaks of perovskite phase were also found in the samples supported on alumina. Temperature programmed profiles of samples revealed the presence of two peaks with maximum at 368 °C and 482 °C. Calcined samples supported on alumina were used in the partial oxidation of methane to evaluate the level of CH4 conversion and selectivity to H2 and CO. LaNiO3 catalyst obtained through chelating precursor method showed the highest performance of methane conversion in the range of 50% and selectivity (about 60%), for 18 h of time reaction.