Redox behaviour of a ceria-zirconia inverse model catalyst

SURFACE SCIENCE

卷:682

Article

Allan, Michael^1,2  Grinter, David³  Dhaliwal, Simran^1,2,3  Muryn, Chris⁴  Forrest, Thomas³  Maccherozzi, Francesco³  Dhesi, Sarnjeet S.³  Thornton, Geoff^1,2 

[1] UCL, Dept Chem, 20 Gordon St, London WC1H 0AJ, England

[2] UCL, London Ctr Nanotechnol, 20 Gordon St, London WC1H 0AJ, England

[3] Diamond Light Source Ltd, Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon, England

[4] Univ Manchester, Sch Chem, Manchester M13 9PL, Lancs, England

关键词: Ceria-zirconia;    Redox;    X-ray photoelectron microscopy;    Oxygen transfer;   

DOI  :  10.1016/j.susc.2018.12.005

来源: Elsevier

【 摘 要 】

The redox behaviour modification following the addition of zirconia to ceria nanostructures supported on Rh (111) has been investigated using a combination of Low Energy Electron Diffraction (LEED) and X-ray Photoemission Electron Microscopy (XPEEM). Soft X-ray irradiation was employed to reduce ZrO2-x(111) supported on Rh(111) and, by introducing oxygen, the reoxidation process of the thin film was monitored. Ceria was then depositied with zirconia. Using XPEEM, we determined that the mixed metal oxide formed a phase-separated structure with CeO2(111) nanoparticles on top of the zirconia. Upon exposure of CeO2-x/ZrO2-x/Rh(111) to X-ray illumination, the zirconia no longer undergoes any observable reduction while at the same time the ceria is reduced. Our results indicate a synergy between the zirconia and ceria in the phase-separated system expected in the working catalyst, with oxygen transfer between the metal oxides. This sheds light on the mechanism of the enhancement of catalytic properties seen with the addition of zirconia to ceria and highlights the oxygen storage and release ability of ceria.

【 授权许可】

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