Shape effect of microstructured CeO2 with various morphologies on CO catalytic oxidation

Novel 3D-like CeO2 microflowers and microspheres were synthesized by facile precipitation methods and tested for CO oxidation. Characterization by UV-Vis, PL, XPS and H2-TPR revealed that 3D-like ceria show great superiority for favoring formation of oxygen vacancies, which in turn leads to higher oxygen mobility and reducibility. A direct relationship between the band gap of ceria and its catalytic activity towards CO oxidation was established. The activity and thermal stability of 3D-like ceria were much better than that of CeO2 nanoparticles. The results indicated that the highly active ceria could be obtained by turning their shapes with a high concentration of oxygen vacancies.

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► Novel 3D-like CeO2 microflowers and microspheres were synthesized by facile precipitation methods and tested for CO oxidation.
► They exhibit an excellent low-temperature activity toward CO oxidation compared with CeO2 nanoparticles.
► A direct relationship was established between the bandgap of CeO2 and its catalytic activity towards CO oxidation.
► The higher activity of CeO2-s or CeO2-f may be attributed to the shape effect of the CeO2 with various morphologies, resulting in the formation of abundant defects in the CeO2.