Tara Boland1 Ethan Lawrence1 Peter Rez1 Peter Crozier1

1, Arizona State University, Tempe, Arizona, United States

Intermediate temperature solid oxide fuel cells (IT-SOFC) are an attractive energy source that can be integrated into the current power generation infrastructure. IT-SOFC are capable of converting a wide range of carbonaceous fuels into energy. CeO2 (ceria) functionalized with catalytic nanoparticles has demonstrated potential as an anode which may be capable of fuel reforming for these systems. Oxygen exchange is a critical reaction that controls the functionality of many oxide-based electrochemical processes. Understanding the key factors which impact the oxygen exchange reaction at the surface is essential in order to integrate and adopt the next generation of fuel flexible, renewable energy technologies. Here we explore how structural motifs evolve on CeO2 surfaces and how these features manifest themselves in high-resolution transmission electron microscope (TEM) images.
To gain fundamental insight into the factors which regulate the oxygen exchange mechanism at various surfaces of ceria nanoparticles, molecular dynamics (MD) simulations will be performed on a number of vacancy configurations. Different vacancy configurations and concentrations will be considered on (111), (110), and (001) surfaces, as well as step edges, to obtain the equilibrated surface structures. The surface energy of each structure will be obtained to evaluate the stability trends for the various proposed structures, as well as the potential energy of edge and corner site atoms. The high resolution TEM images associated with these structural motifs will be simulated and compared with experiment. The structures and simulated images may provide insights into vacancy configurations and will provide a theoretical framework for interpreting experimental images.
[1] We gratefully acknowledge ASU’s HPC staff for support and assistance with computing resources, NSF grant DMR-1308085, and ASU’s John M. Cowley Center for High Resolution Electron Microscopy.