Progress in the synthesis and applications of hexaaluminate-based catalysts

• Published in: Catalysis reviews. Science and engineering Vol. 64; no. 3; pp. 592 - 630
• Main Authors: Torrez-Herrera, J.J., Korili, S.A., Gil, A.
• Format: Journal Article
• Language: English
• Published: New York Taylor & Francis 03.07.2022; Taylor & Francis Ltd
• Subjects: Catalysts; catalytic high-temperature applications; Combustion synthesis; Drying; hexaaluminate; hibonite; High temperature; Insulators; magnetoplumbite; Methane; Oxidation; Reforming; Sol-gel processes; synthesis methods; Thermal resistance; Thermal shock
• ISSN: 0161-4940; 1520-5703
• DOI: 10.1080/01614940.2020.1831756

The development of materials that can exhibit thermal resistance at very high temperatures, thus allowing them to be applied as catalysts and thermal insulators, amongst other possible uses, is a research subject of great interest. This is the case for hexaaluminates, a class of hexagonal aluminate compounds with a unique structure that are stable at very high temperatures up to 1600°C and exhibit exceptional resistance to sintering and thermal shock, thus making them attractive catalysts for high-temperature applications. In this review, the structure of hexaaluminates is presented first. The most recent advances in synthetic methods (sol-gel, reverse microemulsion, hydrothermal synthesis, carbon-templating, solution combustion synthesis, and freeze-drying methods) are discussed subsequently, with the aim of maximizing textural properties and including in their structure metals known to be active in catalytic applications, such as combustion of CH 4 , partial oxidation, and dry reforming of CH 4 to produce synthetic gas, and the decomposition of N 2 O. Finally, other applications, such as their function as a thermal barrier, are also addressed.