Mg改性Silicalite-1分子筛负载Pt-Sn催化剂对异丁烷脱氢性能的影响?

Effects of Mg modification on Pt-Sn loaded silicalite-1 zeolite for isobutane dehydrogenation

利用等体积浸渍法制备不同镁含量的Mg-Silicalite-1 (Mg-SC-1)分子筛,以该分子筛为载体负载Pt-Sn双金属组分催化异丁烷脱氢反应,采用固定床连续反应器评价催化剂性能,并利用X-射线粉末衍射(XRD)、N2吸附-脱附、程序升温还原(H2-TPR)、扫描电镜(SEM)和碳含量分析等方法研究不同MgO含量的Pt-Sn/Mg-SC-1催化剂的催化性能。实验结果表明,添加w(MgO)=7%到SC-1载体,再负载Pt-Sn组分制备的催化剂异丁烷脱氢效果较好,相比于以纯硅SC-1分子筛为载体的催化剂具有高的反应稳定性和活性。而且经Mg改性后的SC-1载体与助剂SnOx物种之间存在较强的相互作用,导致SnOx物种不易被还原,并促进Pt粒子的分散度。在反应12 h后含w(MgO)=7%的Pt-Sn/Mg-SC-1催化剂仍保留较多的活性Pt粒子。

Pt-Sn/Mg-SC-1 catalysts with different magnesium contents were prepared by sequential incipient wetness impregnation,which were evaluated in a micro fixed bed continuous reactor for isobutane dehydrogenation.X-ray powder diffraction(XRD),N2 adsorption-desorption,temperature programmed reduction(H2-TPR),scanning electron microscopy(SEM)and carbon content analysis were used to study the catalytic performance of the Pt-Sn/Mg-SC-1 catalysts.The experimental results indicate that the Pt-Sn/Mg-SC-1 catalyst with w(MgO)=7%exhibits excellent dehydrogenation performance.The characterization results reveal that the interaction between Mg-SC-1 and SnO x species is enhanced,and the SnOx species are not easily reduced,which is beneficial to the dispersion of Pt particles.Moreover,the Pt-Sn/Mg-SC-1 catalysts with w(MgO)=7%has more active Pt particles than other catalysts after 12 h reaction.