Mini Review ARTICLE
Hexagonal Rare Earth-Iron Mixed Oxides (REFeO3): Crystal Structure, Synthesis, and Catalytic Properties
- 1Kyoto University, Japan
The rare earth-iron mixed oxide (REFeO3) is an attractive material in fields such as electronic, magnetic, and catalytic research. Generally, orthorhombic REFeO3 (o-REFeO3) with a perovskite structure is better known than hexagonal REFeO3 (h-REFeO3), because o-REFeO3 is thermodynamically stable for all RE elements. However, h-REFeO3 has a very interesting crystal structure in which a RE and Fe layer are alternately stacked along the c-axis in the unit cell; nevertheless, synthesis of the h-REFeO3 belonging to metastable phase can be problematic. Fortunately, solution-based synthetic methods like solvothermal or co-precipitation synthesis have recently enabled the selective synthesis of h-REFeO3 and o-REFeO3 with comparative ease. Although the electronic and magnetic properties of h-REFeO3 have typically been evaluated, recent research has also revealed excellent catalytic properties that enable environmental cleanup reactions such as hydrocarbon or CO oxidation. This mini-review introduces a synthetic method for controlling the crystal structure between orthorhombic and hexagonal REFeO3 and the catalytic performance of h-REFeO3-based materials.
Keywords: Solvothermal method, coprecipitation method, catalyst, Perovsekite Structure, Hexagonal structure
Received: 19 Jul 2018;
Accepted: 07 Jan 2019.
Edited by:NOBUHITO IMANAKA, Osaka University, Japan
Reviewed by:Tilo Söhnel, The University of Auckland, New Zealand
Roberto Nisticò, Politecnico di Torino, Italy
Shinji Tamura, Osaka University, Japan
Copyright: © 2019 Hosokawa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Saburo Hosokawa, Kyoto University, Kyoto, Japan, email@example.com