Dehydrogenation of propane over PtSnAl/SBA-15 catalysts: Al addition effect and coke formation analysis. Issue 1 (4th September 2014) - Fan, Xiaoqiang
Abstract : Addition of Al to PtSnAl/SBA-15 catalysts inhibits the reduction of SnO x and changes the acidity, which results in different coke formation rates. Abstract : A series of PtSnAl/SBA-15 catalysts were prepared by incipient-wetness impregnation and their catalytic performance was tested for propane dehydrogenation. The catalysts were characterized by XRF, XRD, BET, TEM, UV-vis DRS, NH3 -TPD, O2 -TPO, 27 Al MAS-NMR, XPS and in situ Raman analyses. The addition of aluminum enhances the interaction of the Sn support and consequently stabilizes the oxidation state of Sn during the propane dehydrogenation reaction. The acid centers formed by aluminum addition show close contact with metal centers (Pt), which favors the synergistic effect of the bifunctional active centers. High catalytic performance over PtSnAl0.2 /SBA-15 was obtained, and one-pass propane conversion and propene selectivity are 55.9% and 98.5%, respectively. Moreover, the in situ Raman results indicated the faster coke formation rate of PtSnAl0.4 /SBA-15 than that of PtSnAl0.2 /SBA-15, which may be accelerated by strong acid sites by excess aluminum addition.