High-performance Cr–Zr–O and Cr–Zr–K–O catalysts prepared by nanocasting for dehydrogenation of propane to propene

Abstract

Ordered mesoporous Cr–Zr–O and Cr–Zr–K–O catalysts were prepared by nanocasting using a CMK-3 carbon replica as a hard template. The synthesized oxide nanoreplicas had a uniform pore-size distribution centered in the range of 5.5–6.5 nm and specific surface areas of 123–164 m² g⁻¹. Results of physicochemical characterization (UV-vis DRS, EPR, XRD, XPS and H₂-TPR) revealed that chromium species were stabilized in +3, +5 and +6 oxidation states in all samples. The developed materials exhibited excellent catalytic performance and much higher resistance to deactivation during the process of dehydrogenation of propane to propene in comparison with a material prepared without the CMK-3 hard template assistance. Potassium doping (0.2, 0.5 or 1.0 wt%) of the catalyst with a Zr/Cr atomic ratio of 5 enhanced the selectivity to propene and resistance to coke deposition.