Thermal stability and decomposition kinetics of NdNiO3− δ at 1 bar of O2

• Autor(a) principal: Bassou, A. A.
• Data de Publicação: 2021
• Outros Autores: Machado, P. J., Gomes, M. M., Manjunath, B., Vilarinho, R., Silva, Bruna Andreia Nogueira Airosa, Oliveira, José A., Almeida, B. G., Almeida, A., Fernandes, J. R., Fernandes, L. S., Moreira, J. Agostinho, Tavares, P. B.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/79765
• topic: A. Ceramics; A. Oxides; B. Phase transitions; C. Raman spectroscopy; C. X-ray diffraction; Ceramics; Oxides; Phase transitions; X-ray diffraction; Raman spectroscopy; Ciências Naturais::Ciências Físicas; Science & Technology

Despite the interest in rare-earth nickelates for applications, their processing under 1 bar of oxygen pressure is still challenging. In this work, we report the co-precipitation synthesis, thermal stability and thermally driven decomposition of NdNiO3 phase, in order to determine the synthesis parameters towards a pure perovskite phase. We concluded that using a 1% molar excess of Nd during preparation and posterior annealing at around 900 °C at 1 bar of O2 yields an almost pure NdNiO3−δ phase (with a hexagonal Nd2O3 phase below 0.6% molar), with an oxygen deficiency of δ = 0.082 ± 0.001. The decomposition of the NdNiO3−δ phase into Nd4Ni3O10 and NiO was found to start above 900 °C. On further heating, above 1050 °C, the Nd4Ni3O10 decomposes into Nd2NiO4 and NiO phases. Structural parameters and Raman spectra are provided for the NdNiO3, Nd4Ni3O10 and Nd2NiO4 compounds.