Ceria is widely used catalysis owing to its ability to store and release oxygen and change oxidation state. Defect sites contribute to the water splitting followed by formation of the adsorbed associated intermediate. However, the surface analysis of the defect sites is not an easy task because of the limited number of defects on the surface and non-uniform distribution of the types of defects. In order to accelerate the understanding of chemistry at these sites, the structural configuration and the catalytic chemical behavior should be determined simultaneously with the atomic scale resolution. Scanning tunneling microscope (STM) is a versatile tool for such a purpose, which enables not only the topographic observation of the defects but also characterize chemical state of these sites. In this talk we try to apply the newly developed capabilities of the STM for vibration spectroscopy and spin detection to reveal the chemistry of gas molecules at the defect sites of the ceria surface grown on Pt(111) and Ru(0001) surfaces in the epitaxial manner. These techniques include the inelastic tunneling spectroscopy for the vibrational spectroscopy of the molecule, and Kondo resonance detection to examine the existence of the spin of unpaired orbital. We discuss how such an analysis can contribute to the understanding of the ceria catalysis.

Topographic and spectroscopic investigation of ceria surface by using scanning tunneling microscopy

2019 Fall National Meeting

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