Equilibrium oxygen storage capacity of ultrathin CeO2-δ depends non-monotonically on large biaxial strain

• DOI: 10.1038/ncomms15360
• Publication Date: 2017-05-18T09:48:27Z
• Authors: Chirranjeevi Bala...; Max García-Melchor; Sang Chul Lee; Yezhou Shi; Andrey Shavorskiy; Matteo Monti; Zixuan Guan; Robert Sinclair; Hendrik Bluhm; Aleksandra Vojvodic; William C. Chueh
• Keywords: Tetragonal crystal system

Abstract Elastic strain is being increasingly employed to enhance the catalytic properties of mixed ion–electron conducting oxides. However, its effect on oxygen storage capacity not well established. Here, we fabricate ultrathin, coherently strained films CeO 2-δ between 5.6% biaxial compression and 2.1% tension. In situ ambient pressure X-ray photoelectron spectroscopy reveals up a fourfold enhancement in equilibrium under both This non-monotonic variation with departs from conventional wisdom based chemical expansion dominated behaviour. Through depth profiling, film thickness variations coupled photoemission–thermodynamic analysis space-charge effects, show that enhanced reducibility by interfacial effects. On basis ab initio calculations vacancy formation incorporating defect interactions vibrational contributions, suggest non-monotonicity arises tetragonal distortion large strain. These results may guide rational engineering multilayer core–shell oxide nanomaterials.