Facile one-pot synthesized ordered mesoporous Mg-SBA-15 supported PtSn catalysts for propane dehydrogenation

Abstract

A series of high-surface area and well-ordered mesoporous Mg-incorporated SBA-15 (xMg-SBA-15, x=0, 1, 2, 4 and 6) was prepared using a facile one-pot hydrothermal synthesis method. The resulting materials were used to disperse Pt, Sn particles and further studied the catalytic performance for propane dehydrogenation. The physicochemical properties of the supports and catalysts were characterized by XRD, N2 adsorption-desorption, FT-IR, TEM, NH3-TPD, XPS, H2-TPD and TG-DTA techniques. Compared with the sample synthesized by the impregnation method, the xMg-SBA-15 materials showed a better Mg species distribution and higher specific surface area. It was found that incorporation of appropriate amounts of Mg promoted the dispersion of metallic nanoparticles and facilitated the transfer of the carbon deposits from the active metal to the support. Such a modification of support not only enhanced the interaction of the Sn-support, but also stabilized the oxidation state of Sn species, leading to the improvement of catalytic activity and stability. The significant increases in conversion and selectivity were obtained on the modified catalysts with appropriate content of Mg. The best catalytic performances were obtained on PtSn/2Mg-SBA-15 catalyst with 2wt.% of magnesium, showing a higher than 98% selectivity toward propene at a 38.0% conversion of propane even after 6h reaction.