Shape-controlled ceria-based nanostructures for catalysis applications.

Among oxide catalysts, ceria is a technologically important material because of its wide applications as a promoter in three-way catalysts for the elimination of toxic exhaust gases, low-temperature water-gas-shift reaction, oxygen sensors, oxygen permeation membrane systems, and fuel cells. The catalytic activities of cerium oxide are highly dependent on interfacial structures and nanocrystal morphologies. This Minireview highlights the recent progress in the research of ceria nanoshapes as both catalysts and catalyst supports, including the synthesis, structure characterization, catalytic properties, surface chemistry, as well as reaction mechanisms. Insights from in situ spectroscopy study and theoretical modeling of nanostructured ceria-based materials have shed light on the origin of the ceria shape effect. It is suggested that the surface structure of ceria controls the catalytic activity and selectivity through structure-dependent surface-site geometry, surface vacancy formation energy, defect sites, and coordinatively unsaturated sites on ceria. The morphology-dependent catalysis in ceria has offered a new strategy to finely tune the catalytic activity and selectivity through shape control without altering the catalyst composition. A brief summary and an outlook on this research field will be presented at the end.