Hydrothermal preparation and oxygen storage capacity of nano CeO2-based materials

Nano-powders of NiO-CeO2 and Bi2O3-CeO2 binary compounds for a promoter in the automotive three-way catalysts were synthesized by hydrothermal method. The X-ray diffraction result showed that the average particle size was in the range of 11-12 nm, which was correspondence to the high-resolution transmission electron microscopy result that the average particle size was about 12 nm. The specific surface area of the NiO-CeO2 binary compounds was in the range of 54-75 m(2)/g. Also the average particle size of the Bi2O3CeO2 binary compounds was in the range of 8-11 nm. The oxygen storage capacity of the NiO-CeO2 and Bi2O3-CeO2 binary compounds was investigated under reduction and oxidation conditions. When the Ni and Bi concentration in CeO2 was up to 30%, the OSC values reached 2465 and 2560 mu molO/g separately, which indicated that NiO and Bi2O3 compounded CeO2 materials have fine catalysis activity than other cations doped CeO2-based materials and appear to be very promising for practical applications such as OSC materials.