摘要
A series of CrOy(17.5 wt%)-CeO2(X wt%)/γ-Al2O3 catalysts(X=0,0.5,2,5,8)with various Ce contentswere prepared by a wetness impregnation method and were applied to the dehydrogenation of propane to propylene at 550℃ and 0.1 MPa.The prepared catalysts were characterized by BET,H2-TPR,O2-TPD,XPS,XRD,SEM-EDS and Raman spectroscopy.Among the prepared catalysts,the 17.5Cr-2Ce/Al catalyst with the largest amount of lattice oxygen exhibited the best catalytic performance for the dehydrogenation of propane to propylene with lattice oxygen.The decreased presence of oxygen defects and reducibility were the factors responsible for the improved dehydrogenation activity of the catalysts.The CeO2 layer could inhibit the evolution of lattice oxygen(O2^−)to electrophilic oxygen species(O2^−),and the oxygen defects on the catalyst surfacewere reduced.The inhibited lattice oxygen evolution prevented the deep oxidation of propane or propylene,the average COx selectivity decreased from 24.41%(17.5Cr/Al)to 5.71%(17.5Cr-2Ce/Al),and the average propylene selectivity increased from 60.15%(17.5Cr/Al)to 85.05%(17.5Cr-2Ce/Al).
基金
the support from the National Key Research and Development Program(2018YFB0605401)
Key Research and Development Program of the Ningxia Hui Autonomous Region(2018BCE01002)
National Natural Science Foundation of China(21868025).
