In situ variable temperature X-ray diffraction studies on the transformations of nano-precursors to La-Ni-O phases

Journal Article · Fri Jul 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.04.031· OSTI ID:21580136

Xiaole, Weng ^[1]; Knowles, Jonathan C ^[2]; Abrahams, Isaac ^[3]; Zhongbiao, Wu ^[1]

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1. Department of Environmental Engineering, Zhejiang University, Zhejiang Provincial Engineering Research Center of Industrial Boiler and Furnace Flue Gas Pollution Control, Hangzhou 310027 (China)
2. Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD (United Kingdom)
3. Centre for Materials Research, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

In situ variable temperature XRD (VT-XRD) measurements on the transformation of nano-precursors to La-Ni-O phases are presented. Experimental results showed that LaNiO{sub 3} and La{sub 2}NiO{sub 4} phases were formed at ca. 700 deg. C via the reaction of La{sub 2}O{sub 3} and NiO (from the initial nano-precursors), where a relatively low temperature of 700 deg. C was found for the synthesis of La{sub 2}NiO{sub 4}. The formation of La{sub 3}Ni{sub 2}O{sub 7} at higher temperature (up to 1150 deg.C) appeared to proceed through a further reaction of La{sub 2}NiO{sub 4} with unreacted NiO, whilst the formation of La{sub 4}Ni{sub 3}O{sub 10} (at 1075 deg. C) proceeded via a further decomposition of LaNiO{sub 3}. Although phase pure La{sub 3}Ni{sub 2}O{sub 7} and La{sub 4}Ni{sub 3}O{sub 10} were not directly obtained under the processing conditions herein, the results of this study allow for a better understanding of formation pathways, particularly for the higher order La-Ni-O phases. - Graphical abstract: In situ variable temperature XRD showing the phase formation pathway of La{sub n+1}Ni{sub n}O{sub 3n+1} at evaluated temperatures. Highlights: > In situ VT-XRD was utilized to study the pathways for La{sub n+1}Ni{sub n}O{sub 3n+1} formations. > LaNiO{sub 3} and La{sub 2}NiO{sub 4} phases were formed via the reaction of La{sub 2}O{sub 3} and NiO, respectively. > La{sub 3}Ni{sub 2}O{sub 7} phase was formed via further reaction of La{sub 2}NiO{sub 4} phase with unreacted NiO. > La{sub 4}Ni{sub 3}O{sub 10} phase was formed via further decomposition of LaNiO{sub 3} phase.

• OSTI ID: 21580136
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 7; Other Information: DOI: 10.1016/j.jssc.2011.04.031; PII: S0022-4596(11)00199-X; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DECOMPOSITION
FUEL CELLS
LANTHANUM OXIDES
NICKEL OXIDES
PEROVSKITES
POWDERS
PRECURSOR
SOLIDS
SYNTHESIS
TEMPERATURE RANGE 0065-0273 K
TRANSFORMATIONS
X RADIATION
X-RAY DIFFRACTION
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
DIRECT ENERGY CONVERTERS
ELECTROCHEMICAL CELLS
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
LANTHANUM COMPOUNDS
MINERALS
NICKEL COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
RARE EARTH COMPOUNDS
SCATTERING
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS