Efficient Dehydrogenation\nof Propane to Propene over\nPtIn Nanoclusters Encapsulated in Hollow-Structured Silicalite‑1

Pt-based catalysts have been widely used for propane\ndehydrogenation\nto propene. However, the high reaction temperature generally induces\nserious sintering and agglomeration of metal species, thus leading\nto rapid deactivation of the catalysts. Herein, PtIn nanoclusters\n(NCs) encapsulated in hollow-structured silicalite-1 (designated as\nPtIn@S1–H) was prepared using recrystallization method. This\nmaterial shows high catalytic performance in propane dehydrogenation.\nThe propane conversion and propene selectivity reach ∼45–47.5%\nand ∼99%, respectively, at 547 °C at least within 167.6\nh. As a result, it displays a significantly higher specific activity\nfor C<sub>3</sub>H<sub>6</sub> formation (0.37–0.59 s<sup>–1</sup>) than Pt@S1, Pt@S1–H, and other reported Pt-based catalysts.\nNotably, its catalytic performance is well maintained for more than\n3600 h, with propane conversion of ∼31–34% and propene\nselectivity of ∼91–95%, when pure propane is fed. More\ninterestingly, this catalyst can be reused through regeneration. EXAFS,\nHAADF-STEM and DFT calculation, and AIMD simulation results show that\nhollow-structured silicalite-1 crystal morphology not only facilitates\nthe formation of Pt<sub>5</sub>In<sub>3</sub> alloy NCs but also inhibits\nNC aggregation and growth. PtIn@S1–H showed a TON ≥\n38996 in contrast to 5367, 4928, 798, and 542 obtained on PtIn@S1,\nPtSn@S1, PtSn/Al<sub>2</sub>O<sub>3</sub>, and PtIn/Al<sub>2</sub>O<sub>3</sub>, respectively, if the catalysts were considered to\nbe deactivated when the propane conversion was decreased by 15%. This\nis because alloying of In into Pt NCs weakens the interaction of C<sub>3</sub>H<sub>7</sub>* intermediates with metallic Pt NCs and the\nadsorption of C<sub>3</sub>H<sub>6</sub> on the catalyst surface,\nthus suppressing the C<sub>3</sub>H<sub>7</sub>* cleavage reaction\nand enhancing propane activation and propene selectivity.