Enhancing the propane dehydrogenation performance of PtSn/Al2O3 catalysts by constructing spherical Al2O3 with a hierarchical porous structure and high AlV content

Abstract

The dispersion and anti-sintering capability of Pt particles as well as the diffusion rates of reactants and products are critical factors influencing the catalytic activity of PtSn/Al₂O₃ catalysts employed in the propane dehydrogenation reaction. These properties are closely associated with the porous structure and the surface coordination structure of the aluminum ions of an Al₂O₃ support. In this study, millimeter-sized spherical alumina was synthesized and modified by incorporating MIL-96(Al) during preparation to enlarge its pore size and promote the formation of pentacoordinated aluminum ions (Al_V). The influence of the derived alumina on the propane dehydrogenation performance of PtSn/Al₂O₃ catalysts was systematically investigated. The results indicated that the incorporated Al-MOF facilitated the creation of a hierarchical porous structure, comprising mesopores originating from native γ-Al₂O₃ and macropores formed through the decomposition of the Al-MOF. Furthermore, catalysts incorporating Al-MOFs exhibited a higher content of Al_V compared to bare γ-Al₂O₃. The hierarchical porous structure and increased Al_V content significantly improved the dispersion of Pt particles, reduced the size of Pt particles, and improved the resistance to Pt particle sintering. These structural advantages led to notable improvement in catalytic activity. The optimal catalyst, PtSn/Al₂O₃(0.2AlMOF), achieved an initial propane conversion of 42.3% and demonstrated excellent regenerability, showing great promise for industrial application.