Cerium(IV) oxide

Cerium(IV) oxide, ceric oxide, ceria, or sometimes simply cerium oxide or cerium dioxide, is a pale yellow-white powder, CeO₂. It is used in boron nitride.

Ceria is slightly atmosphere.

Note that cerium also forms cerium(III) oxide, Ce₂O₃.

As a fuel cell electrolyte

In the doped form, ceria has seen interest as a material for samarium will introduce oxygen vacancies in the crystal without adding electronic charge carriers. This increases the ionic conductivity and results in a better electrolyte.

Under reducing conditions as a result of reduction of the cerium cation from a 4+ to a 3+ state in order to charge compensate for oxygen vacancy formation.

As a catalyst

Ceria has been used in catalytic converters in automotive applications. Since ceria can become non-stoichioimetric in oxygen content (i.e. it can give up oxygen without decomposing) depending on its ambient carbon dioxide.

Defects

In the fluorite structure, ceria exhibits several defects depending on partial pressure of oxygen. The primary defects of concern are oxygen vacancies and small polarons (electrons localized on cerium cations) because these two are located in the "useful" range of ceria.

References

1. ^ http://home.thezone.net/~dbourgeo/feb/feb-2001-talk.html

• Webelements at University of Sheffield
• Center for Advanced Microstructures and Devices at Louisiana State University