VMOF derived VOx/Al2O3 millimeter spherical catalyst for propane dehydrogenation with enhanced activity and stability

VMOF derived VOx/Al2O3 millimeter spherical catalysts were prepared using MIL-100(V) as precursor by gum arabic-assisted sol-gel and N2-air dual calcination method, and the effects of preparation method and V loading of catalyst on the properties of VOx/Al2O3 and propane dehydrogenation performance were investigated systematically. The as-prepared spherical catalyst exhibited a watermelon-seed-like structure with VMOF derived VOx as seeds, and isolated VOx species with good dispersion could be achieved even at a higher vanadium loading owing to the isolation effects of organic ligands of MOF and alumina support. The hierarchical porous structure with mesopores of alumina and micro-scale rod-like pores left by the decomposition of MIL-100(V) through N2air dual calcination could be created. Besides, weaker interaction between VOx derived from MOF and alumina is beneficial for increasing the amount of reducible isolated species and decreasing strong acid site amount. 7.4VOx/Al2O3 presented the highest catalytic performance with propane conversion of 30.8 %/28.2 % (initial/ final) and propylene selectivity of 91.6 %/94.7 % (initial/final) within 5.25 h reaction due to the good dispersion of VOx species, hierarchical porous structure and moderate amount of surface acid sites. The high stability and excellent reaction-regeneration cycle performance of 7.4VOx/Al2O3 offered a great potential for the industrial application of vanadium-based catalysts in the propane dehydrogenation reaction.