Author(s):
Bassou, A. A. ; 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.
Date: 2021
Persistent ID: https://hdl.handle.net/1822/79765
Origin: RepositóriUM - Universidade do Minho
Subject(s): A. Ceramics; A. Oxides; B. Phase transitions; C. Raman spectroscopy; C. X-ray diffraction; Ceramics; Oxides; Phase transitions; X-ray diffraction; Raman spectroscopy
Description
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.
