Investigating the Grain Boundaries of a Doped Ceria Solution from a Model

David S. Mebane, *Abednego S. Abdi*
Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506

Presentation Category: Engineering (Poster Presentation)

Student’s Major: Mechanical and Aerospace Engineering

Cerium dioxide (CeO2), commonly referred to as ceria, is a robust conductor of both ionic and electronic current due to its cubic fluorite structure and capacity to accommodate electrons as Ce3+. Its mixed conductivity makes it a favorable catalyst, used in the catalytic converters in cars which oxidize harmful gases in the exhaust. The speed of these electron and oxygen “flows” have been observed to be faster within the bulk region of the crystals compared to the grain boundaries in the polycrystalline ceramic. Ionic conductivity can be induced by introducing a dopant like gadolinium oxide (Ge2O3) before sintering at high temperatures. Electron microscopy techniques are capable of observing concentrations of the dopant species as a function of distance from the grain boundary. A thermodynamic model developed in the Energy Systems and Materials Simulation group can predict these concentration profiles. The SURE project modified a program based on these unorthodox thermodynamic models so that it could be used to analyze transmission electron microscope data generated by collaborators at the University of California at Irvine.

Funding:

Program/mechanism supporting research/creative efforts: a West Virginia SURE program