Effect of calcination temperature on catalytic properties of PtSnNa/ZSM-5 catalyst for propane dehydrogenation

The effect of calcination temperature on catalytic performance of PtSnNa/ZSM-5 catalysts for propane dehydrogenation was studied. It was found that when the calcination temperature was in the range of 400–500°C, structure and acidity of the catalyst did not change obviously. In contrast to this, with the increase of calcination temperature, the specific surface area and pore volume dramatically decreased, while the mean pore diameter increased. Under these conditions, more framework aluminum atoms were removed from tetrahedral positions, which weakened the interactions between Sn species and carrier. Meantime, the degree of Pt sintering and the destruction of Pt active sites with “sandwich structure” were aggravated, which was disadvantageous to the reaction. When the catalyst was calcined at 500°C, the interactions between Pt and Sn were strengthened, thus improving the catalytic stability and reaction selectivity evidently. Moreover, it should be remarked that the phenomenon of slow Pt sintering was not clearly observed even though the reaction temperature of it was higher than the calcination one.