Visualizing Anisotropic Oxygen Diffusion in Ceria under Activated Conditions
Liang Zhu, Xin Jin, Yuyang Zhang, Shixuan Du, Lei Liu, Tijana Rajh, Zhi Xu, Wenlong Wang, Xuedong Bai, Jianguo Wen, Lifen Wang
Abstract
Oxygen reactivity plays a key role in the performance of ceria-based catalysts. Aberration-corrected transmission electron microscopy and molecular dynamics simulations were used to study the oxygen atom diffusion in ceria under activated conditions. Reactive oxygen atom and its real-time diffusion were visualized. The interplay between cerium and oxygen atoms originating from a Coulomb interaction was revealed by the out-of-plane buckling of cerium atoms associated with oxygen transport. Anisotropic oxygen atom diffusion that depends on crystal orientations was discovered, demonstrating a preferential [001] crystallographic diffusion pathway. These findings reveal prospects for applications of anisotropic orientation-relevant fluorite-structured oxides.