Effect of Si/Al ratio of β zeolite on propane dehydrogenation without H₂ over PtZn catalyst

In this study, the PtZn/β-x catalysts (x refers to SiO₂/Al₂O₃ mole ratio) were synthesized by co-impregnation method and the effect of Si/Al ratio of the β zeolite on propane non-hydrogen dehydrogenation was explored. A series of characterization such as XRD, BET, HAADF-STEM, NH₃-TPD, C₃H₆-TPD were applied to investigate the phase structure, surface properties of catalysts, and their effects on the reaction performances. The results showed that, with the increase of Si/Al ratio, the catalytic stability would be enhanced following the order of PtZn/DeAl-β > PtZn/β-40 > PtZn/β-30 > PtZn/β-25, while the number of strong acid sites of the catalyst (PtZn/β-30 > PtZn/β-40 > PtZn/β-25 > PtZn/DeAl-β) was affected by the Si/Al ratio to some extent, which was opposite to the order of the propylene selectivity. Therefore, the control of the Si/Al ratio of zeolite is very important for optimizing the properties of the catalysts for propane dehydrogenation reaction. The catalysts with few strong acid sites, weak adsorption of propylene and large specific surface area are contributed to higher propane conversion, propylene selectivity and catalytic stability.