Enhanced oxygen storage capacity of Ce0.88Mn0.12Oy compared to CeO2: An experimental and theoretical investigation

Ce0.88Mn0.12Oy and CeO2 nanoparticles have been successfully prepared via a supercritical antisolvent process. High-resolution transmission electron microscopy displays the hollow and spherical structures of these nanoparticles. X-ray diffraction analysis demonstrates the formation of Ce0.88Mn0.12Oy solid solution. N2 adsorption reveals that the Ce0.88Mn0.12Oy has nearly the same surface area with the CeO2. It is shown that the Ce0.88Mn0.12Oy has higher oxygen storage capacity (OSC) than the CeO2. To understand the mechanism of the improved OSC of the Mn doped CeO2, Raman spectroscopy, X-ray photoelectron spectra and density functional theoretical (DFT) calculations have been performed. It is found that the Ce0.88Mn0.12Oy presents more oxygen vacancies, indicating the easier of oxygen mobility from bulk to surface. DFT calculations reveal that structural and electronic modifications are caused by the incorporation of Mn in the CeO2, resulting in activated oxygen species. The oxygen vacancy formation energy is lowered by the Mn doping. These changes are responsible for the enhanced OSC of the Ce0.88Mn0.12Oy.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ce0.88Mn0.12Oy and CeO2 hollow nanospheres were successfully prepared via a supercritical antisolvent process. ► Compared with the pure CeO2, the Ce0.88Mn0.12Oy has nearly the same surface area but more oxygen vacancies. ► DFT calculations shows that the surface oxygen of the CeO2 gets activated after doping Mn.