Ceria-Based Materials in Catalysis

First commercial use of ceria dates back to the late 1970s when CeO2 was employed as an oxygen storage component of three-way catalysts formulation. The ability of ceria to modify the oxidation state in a suitable temperature range by maintaining structural integrity is the key of its success. There are now several other applications or processes for which ceria-based materials are being actively investigated. CeO2 is used as component in catalyst materials for soot oxidation, reforming, partial oxidation, and water–gas shift reaction. Other energy-related uses are in the fuel cell technology or in the thermochemical water splitting where CeO2-based materials are fundamental components to reduce the operating requirements. All these applications benefit primarily from the unique redox properties of cerium dioxide and from the possibility of fine-tuning the interaction between ceria and other elements in order to improve catalytic performances. Additional effects, like stabilization of metal dispersion, change of crystal shape/morphology, and structural/textural stability, can affect catalytic properties as well. Some of these issues will be reviewed, with a special focus on the understanding of the relationships between activity and morphology and trying to see how the tremendous growth experienced within ceria-based materials can help in determining future developments.