Evaluation of cordierite–ceria composite ceramics with oxygen storage capacity

Oxygen storage capacity (OSC) is an important parameter in three-way-catalysts (TWCs) for the purification of exhausts from gasoline engines of automobiles. Beciuse CeO2 possesses the unique performance, it is added into catalytic coatings of converters to adjust the oxygen concentration of the exhausts. However, small amounts of CeO2 existing in the coating is insufficient in this when air-fuel ratio fluctuates in a relatively wide range. In the present work, a kind of cordierite–CeO2 ceramic was prepared through sol-gel method so as to append the OSC to the support on which the catalyst is coated. Advanced measurement techniques such as XRD, SEM and gas chromatograph were employed to evaluate the microstructure and properties of the composite ceramics. Results show that the composite ceramics consist both phases of cordierite and CeO2. CeO2 particles are uniformly and separately distributed in the cordierite matrix, their number and granularity dependent on the amount of Ce4+ addition. The cordierite and 10 wt.% CeO2, possesses an apparent OSC, appropriate porosity, flexural strength and thermal expansion coefficient. It will be helpful to enhance the OSC of the catalytic converters and so improve the purification effects to the exhausts.