Relationship between Surface Chemistry and Catalytic Performance of Mesoporous γ-AlO Supported VO Catalyst in Catalytic Dehydrogenation of Propane.

Mesoporous γ-AlO was synthesized via a cation-anion double hydrolysis approach (CADH). The synthesized mesoporous alumina displayed a relatively high surface area, a large pore volume and a narrow pore size distribution. By applying the mesoporous alumina as a support, supported vanadium catalysts were prepared and evaluated in the dehydrogenation of propane, exhibiting a superior catalytic performance over that supported on a commercial alumina. Materials were characterized with a variety of techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, V magnetic angle spinning nuclear magnetic resonance, Raman spectroscopy, Fourier transformed infrared spectroscopy of pyridine adsorption and thermogravimetric-differential thermal analysis. The correlated structure-performance relationship of catalysts reveals that a higher crystallization temperature endows mesoporous alumina materials with more surface acid sites, favoring the formation of polymerized VO species, which are more active than isolated ones in the propane dehydrogenation, resulting in a better catalytic performance. The established relationship between surface chemistry and catalytic performance of supported VO catalysts suggests that a superior vanadium catalyst for propane dehydrogenation could be achieved by rationally enriching the concentration of polymeric VO species on the catalyst, which can be realized by tuning the surface acidity of alumina support.