engleski

Improved thermal stability of manganese-doped ceria prepared by sol-gel synthesis

Ceria (CeO2) with its versatile physical and chemical properties is convenient for many industrial and ecofriendly applications such as solid oxide fuel cells, catalysis, oxygen permeation membrane systems etc. Volatile organic compounds (VOC), carbon monoxide (CO), soot and many other compound oxidation can be catalysed by ceria. Most of its advantageous properties are associated with oxygen vacancies formation. The shift between Ce3+ and Ce4+ results in oxygen vacancies and because of the easy shift, oxygen storage and also high oxygen mobility within the ceria lattice are ensured. Furthermore, doping with various metals is known to enhance oxygen storage capacity and increase the catalytic activity. Manganese oxides are also known for their thermal stability and have good catalytic properties due to the appearance in various oxidation states. There are many ways of gaining nanosized cerium oxide: precipitation, thermal decomposition, sol-gel, hydrothermal synthesis and many others. Sol-gel synthesis is used because it allows better control of the reactions during synthesis, it is conducted at low temperatures and possible outcomes can be engineered by changing the parameters. In this work ceria nanoparticles doped with manganese in various amounts were prepared by sol-gel synthesis. The prepared were analysed by X-ray diffraction (XRD) and turned out to be amorphous with traces of organic precursors. The presence of organics was investigated by infrared spectroscopy with Fourier transformation (FTIR). Thermally induced changes were monitored via differential thermal analysis and thermo-gravimetric analysis (DTA/TGA) which gave insight into crystallization of ceria from amorphous gel. Thermal treatment of the prepared samples yield with nanocrystalline CeO2.Crystallite sizes calculated by Scherrer equation indicates improved thermal stability of doped samples. Improved thermal stability was confirmed through grain growth analysis in non-isothermal conditions.

Sol-gel ; doping ; ceria ; maganese

nije evidentirano