丙烷脱氢负载型PtSnNa/SUZ-4催化剂中Na+助剂组分的作用

用微型催化反应装置结合X射线衍射(XRD)、H₂化学吸附、NH₃吸附-程序升温脱附(NH₃-TPD)和H₂-程序升温还原等多种物理化学手段研究了丙烷脱氢负载型PtSnNa/SUZ-4催化剂中Na⁺助剂组分的作用。结果表明,Na⁺组分可中和SUZ-4载体表面的强酸中心、提高催化剂的Pt金属分散度、抑制脱氢产物的裂解和积炭的生成,从而提高催化剂的丙烷脱氢选择性和反应稳定性。但是过量Na⁺组分的存在会削弱Sn物种与载体之间的相互作用,使其易被还原,导致催化剂丙烷脱氢活性显著下降。

Promotional effect of Na+ in the supported PtSnNa/SUZ-4 catalysts for propane dehydrogenation

The promotional effects of Na⁺ component in the supported PtSnNa/SUZ-4 catalysts for propane dehydrogenation have been studied by using X-ray diffraction (XRD), H₂ chemisorption, NH₃ temperature-programmed desorption (NH₃-TPD) and H₂ temperature-programmed reduction (H₂-TPR) combined with microreator tests. It has been shown that Na⁺ component in the supported PtSnNa/SUZ-4 catalysts can neutralize the strong acidic sites on the surface of SUZ-4 zeolite support, increasing the Pt dispersion and suppressing the cracking of olefin products and the formation of coke, leading to the increases of propene selectivity and catalytic stability. But, excessive Na⁺ ions in the catalyst decreases the interaction between Sn component and SUZ-4 zeolite support, resulting in the drastic decrease of catalytic activity for propane dehydrogenation.