Influence of Ce Doping on the Activity of Ce-Cr/S-1 Catalysts for the Oxidative Dehydrogenation of Propane with CO2

Abstract

A Ce-modified Cr-based catalyst supported on Silicalite-1 (S-1) zeolite was synthesized and used for CO₂-ODP (CO₂-assisted oxidative dehydrogenation of propane). Then, reaction and calcination temperature effects on catalytic performance were further studied. The structure of the catalyst was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction of hydrogen (H₂-TPR), and diffuse reflectance ultraviolet-visible spectroscopy (UV-vis). The results show that the distribution of Cr on the catalyst's surface and the amount of lattice oxygen can be changed by introducing Ce into the catalyst to modify the catalyst. After Ce modification, more polymerized Cr⁶⁺ sites and lattice oxygen were formed on the catalyst's surface, which was conducive to increasing the activity and selectivity of the catalyst and reducing the amount of carbon deposition on the catalyst surface. By decreasing the calcination temperature, the amount of polymerized Cr⁶⁺ sites and lattice oxygen can be further increased.