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

Abstract

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 xCr/Al₂O₃ catalysts with hierarchical spindle-like morphology have high specific area and highly dispersed chromia on the surface of γ-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.