engleski

Combustion synthesis of copper-doped cerium aluminate

Intensive use of internal combustion vehicles has caused significant air pollution, which is a major environmental problem of modern society. As a potential solution, various exhaust gas purification systems have been developed, such as three-way catalytic (TWC) converters for automobile exhaust systems. Important parts of this catalytic systems are alumina (Al2O3) support with a large surface area and ceria (CeO2) serving as oxygen storage promotor. Combustion synthesis is a simple, inexpensive method which enables the preparation of highly porous materials with good control over their composition, homogeneity and particle size. Our previous research focused on the preparation of ceria-alumina mixed oxides with addition of other catalytically active substances such as Cu and Mn. The addition of copper proved extremely beneficial resulting in a higher reaction temperature and less unreacted residue, with the main reaction product being cerium aluminate (CeAlO3), a perovskite-type material which is used in TWC converters and solid oxide fuel cells. [1] In this work, CeAlO3 doped with different amounts of Cu (0, 0.5, 1 and 2 mol. %) was prepared by combustion synthesis using metal nitrates as oxidants and glycine as fuel. The prepared samples were analyzed using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), differential thermal and thermogravimetric analysis (DTA-TGA) and Fourier transformed infrared spectroscopy (FTIR). The XRD analysis showed that the samples with 0 and 0.5 mol. % of Cu consist only of ceria, which means that the combustion temperature was not sufficient for Al2O3 crystallization or CeAlO3 formation. On the other hand, 1 and 2 mol. % Cu doped samples consist of CeAlO3 phase. The higher is the amount of Cu, the higher is the reaction temperature, as well as crystallinity and porosity of the obtained CeAlO3, while there is consequently less remaining organics and nitrates in the samples. The DTA-TGA analysis showed that CeAlO3 decomposes to CeO2 and Al2O3 above 800 °C.

cerium aluminate ; copper ; combustion synthesis

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