Hydrothermally prepared chromia-alumina (xCr/Al2O3) catalysts with hierarchical structure for propane dehydrogenation

Propane dehydrogenation was investigated over a series of chromia-alumina (xCr/Al2O3) catalysts containing 2.5-10 wt% chromium (Cr), synthesized via a hydrothermal synthesis method. The synthesized Al2O3 catalysts with hierarchical spindle-like morphology have high specific area and highly dispersed chromia on the surface of gamma-Al2O3. Besides, the higher Cr6+/Cr3+ ratio is advantageous to obtain higher propane conversion and lower propylene selectivity. The synthesized 7.5Cr/Al2O3 catalyst exhibits the highest propane conversion of 62% accompanied by 89% propylene selectivity at 873 K. After regenerated by re-calcinating in air, the original activity of the spent catalyst is well recovered.