Zr-doped CeO₂ nanorods as versatile catalyst in the epoxidation of styrene with tert-butyl hydroperoxide as the oxidant

The CeO₂ nanorods with various Zr dopant concentrations were studied in terms of their activity in the selective oxidation of styrene to styrene oxide using tert-butyl hydroperoxide as the oxidant. Several techniques were used to characterize the synthesized Zr-doped CeO₂ nanorods. The results indicated that Zr ions were doped into the ceria lattice and formed fluorite-like solid solutions, resulting in an increase in oxygen vacancy concentration. It was also found that Zr content has a significant impact on intrinsic natures of the catalyst, namely, the specific surface area, oxygen vacancy concentration and the content of Ce³⁺ ions, which were found to determine the catalytic efficiency of the catalyst in the epoxidation of styrene. It is interesting that the remarkably increased catalytic performance of the ceria nanorods with 10 mol% zirconium is mainly attributed to the more oxygen vacancy and the higher percentage of Ce³⁺. Furthermore, recycling studies proved the heterogeneous zirconium-doped ceria nanorods did not lose the initial high catalytic activity after five successive recycles.