Synthesis of CeO2-Fe2O3 nanocomposites via controllable oxidation of CeFeO3 nanocrystals

This work presents an innovative way of preparation preceramic nanocomposites based on CeO2 and Fe2O3 with an extremely low surface area (0.027-0.262 m(2)/g) and pore volume (0.4-5.0-10(-4) cm(3)/g). Preceramic nano composites were synthesized by the high-temperature oxidation of CeFeO3 nanocrystals in the air. Crystals of CeO2 and Fe2O3 in nanocomposites have a spherical morphology with an average crystallite size of 4-6 nm and 40-47 nm for 700 and 900 degrees C treatment temperatures correspondingly. Fine ceramics based on the CeO2 and Fe2O3 with submicron grain size were obtained via sintering of the compacted preceramic nanopowders at 1000 degrees C for 4 h. It was shown that depending on the synthesis temperature of the preceramic nanocomposites ceramics with low (0.7-1.0 W/m.K) and high (2.3-4.3 W/m.K) thermal conductivity in the temperature range of 25-600 degrees C can be obtained. So, a novel approach for the synthesis of CeO2/Fe2O3-based ceramics with controlled heat-conducting properties was proposed. The resulting ceramics can be considered as the perspective material for chemical-looping steam methane reforming (CL-SMR).