Hydrothermal Preparation and Oxygen Storage Capacity of Nano CeO2-based Materials

Abstract

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 1112 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 5475 m2/g. Also the average particle size of the Bi2O3-CeO2 binary compounds was in the range of 811 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 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.

Ceria Nanocrystals Supporting Pd for Formic Acid Electrocatalytic Oxidation: Prominent Polar Surface Metal Support Interactions

“…It is noted that the maintenance of the Ce 3+/ Ce 4+ ratio, around 0.3 (Ce 2 O 3 ), around the top surface of the previously reduced state in Figure d despite being in an O 2 atmosphere implies that the reoxidation of Ce 3+ to Ce 4+ catalyzed by Pd is not yet completed from the extensively reduced inner layers created from the previous reduction treatment. This result echoes the reported surface properties of ceria with high oxygen storage capacity of (100) ceria surface and high mobility of oxygens at noble metal–ceria interface to resist the change in metal oxidation state . This means a significant amount of O species on Pd is rapidly spilling and replenishing the oxygen vacancies to ceria nanoparticle via this ceria cubes (100) surface during the dynamic reoxidation process to maintain the higher content of Pd 0 .…”