Promoting effect of Fe in oxidative dehydrogenation of ethylbenzene to styrene with CO2 (I) preparation and performance of Ce1 − xFexO2 catalyst

• The formation of Ce–Fe solid solutions could create more oxygen vacancies.
• Oxygen vacancies can promote the absorption and activation of CO2.
• The high transmission capacity of oxygen promoted the activity of catalysts.

To improve the lattice structure of CeO2 and the transmission capacity of oxygen, Ce1 − xFexO2(x ≤ 0.2)solid solutions were prepared by a hydrothermal method and used in oxidative dehydrogenation of ethylbenzene to styrene with CO2. Ce1 − xFexO2 solid solutions were characterized by powder X-ray diffraction, Raman spectroscopy, N2-adsorption, H2 temperature-programmed reduction and H2–O2 titration. Results showed that approximately 20% of Fe3 + could dissolve into the CeO2 lattice while portions of Fe2O3 were highly dispersed on the surface of the Ce1 − xFexO2 solid solution. The formation of Ce–Fe solid solutions could create more oxygen vacancies to promote the absorption and activation of CO2, which improves the activity of the catalyst and increased ethylbenzene conversion by as much as 13%.

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