Oxygen storage capacity and thermal stability of brownmillerite-type Ca2(Al1-xGax)MnO5+δ oxides
Abstract
Understanding the oxygen uptake/release mechanism in oxygen storage materials is of great importance in the design of energy-related materials and their corresponding applications. In this work, the effects of Ga doping amount on the oxygen storage capacity and thermal stability of Ca2(Al1-xGax)MnO5+δ (0 ≤ x ≤ 1) with a brownmillerite-type structure were investigated. Ca2AlMnO5+δ can reversibly store/release a large amount of excess oxygen (∼3.0 wt%) at low temperature (between 300 and 600 °C) under oxidative atmospheres. With the increasing Ga doping amount in Ca2(Al1-xGax)MnO5+δ, these materials uptake less oxygen at higher temperature which can be attributed to the difficulty in the oxidation of tetrahedral GaO4 blocks into octahedral GaO6 blocks under 1 atm O2. However, with the increasing of Ga-substitution amount, these Ca2(Al1-xGax)MnO5+δ (0 ≤ x < 1) can start to uptake oxygen at lower temperatures during the cooling process under flowing O2 due to the distorted structure. The results demonstrated that Ca2(Al1-xGax)MnO5+δ (0 ≤ x < 1) can reversibly store/release large amounts of oxygen via just controlling the surrounding temperature and/or oxygen partial pressure but without using reductive gases, which would enable them great potentials in many applications.
Citation
Huang , X , Ni , C & Irvine , J T S 2019 , ' Oxygen storage capacity and thermal stability of brownmillerite-type Ca 2 (Al 1-x Ga x )MnO 5+δ oxides ' , Journal of Alloys and Compounds , vol. 810 , 151865 . https://doi.org/10.1016/j.jallcom.2019.151865
Publication
Journal of Alloys and Compounds
Status
Peer reviewed
ISSN
0925-8388Type
Journal article
Description
The authors gratefully thank the National Natural Science Foundation of China (No. 51802015), and the Engineering and Physical Sciences Research Council platform grant (EP/I022570/1 and EP/I022570/2) for financial support.Collections
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