CeO2‐CrOy/γ‐Al2O3 redox catalyst for the oxidative dehydrogenation of propane to propylene

Abstract CeO 2 ‐CrO y loaded on γ‐Al 2 O 3 was investigated in this work for the oxidative dehydrogenation (ODH) of propane under oxygen‐free conditions. The ODH experiments of propane were conducted in a fluidized bed at 500°C‐600°C under 0.1 Mpa. The prepared catalyst was characterized by N 2 adsorption‐desorption measurements, H 2 ‐temperature‐programmed reduction, O 2 ‐temperature‐programmed desorption, NH 3 ‐temperature‐programmed desorption, x‐ray photoelectron spectroscopy, and x‐ray diffraction. The change in the selectivity of propylene resulted from the thermal cracking of the propane and the competition for lattice oxygen in the catalyst between propylene formation and propane and propylene combustion. Therefore, to achieve higher propylene yield in the industry, the reaction temperature should be 550°C‐575°C for the 17.5Cr‐2Ce/Al catalyst. The results of H 2 ‐TPR (from 0.2218 mmol/g‐0.3208 mmol/g) revealed that the addition of CeO 2 can enhance the oxygen capacity of CrO y . Compared with that for 17.5Cr/Al, the conversion can be enhanced from 22.4% to 28.5% and the selectivity of propylene can be improved from 72.2% to 75.9% for the 17.5Cr‐2Ce/Al catalyst. In addition, CeO 2 can inhibit the evolution of lattice oxygen (O 2− ) to electrophilic oxygen species (O 2 − ), causing the average CO x (CO and CO 2 ) selectivity to decrease from 9.64% to 6.31%.