Pt-based catalysts have been widely used for propane dehydrogenation to propene. However, the high reaction temperature generally induces serious sintering and agglomeration of metal species, thus leading to rapid deactivation of the catalysts. Herein, PtIn nanoclusters (NCs) encapsulated in hollow-structured silicalite-1 (designated as PtIn@S1–H) was prepared using recrystallization method. This material shows high catalytic performance in propane dehydrogenation. The propane conversion and propene selectivity reach ∼45–47.5% and ∼99%, respectively, at 547 °C at least within 167.6 h. As a result, it displays a significantly higher specific activity for C₃H₆ formation (0.37–0.59 s^–1) than Pt@S1, Pt@S1–H, and other reported Pt-based catalysts. Notably, its catalytic performance is well maintained for more than 3600 h, with propane conversion of ∼31–34% and propene selectivity of ∼91–95%, when pure propane is fed. More interestingly, this catalyst can be reused through regeneration. EXAFS, HAADF-STEM and DFT calculation, and AIMD simulation results show that hollow-structured silicalite-1 crystal morphology not only facilitates the formation of Pt₅In₃ alloy NCs but also inhibits NC aggregation and growth. PtIn@S1–H showed a TON ≥ 38996 in contrast to 5367, 4928, 798, and 542 obtained on PtIn@S1, PtSn@S1, PtSn/Al₂O₃, and PtIn/Al₂O₃, respectively, if the catalysts were considered to be deactivated when the propane conversion was decreased by 15%. This is because alloying of In into Pt NCs weakens the interaction of C₃H₇* intermediates with metallic Pt NCs and the adsorption of C₃H₆ on the catalyst surface, thus suppressing the C₃H₇* cleavage reaction and enhancing propane activation and propene selectivity.

中文翻译：

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在封装在空心结构硅石-1 中的 PtIn 纳米团簇上丙烷高效脱氢制丙烯


铂基催化剂已广泛用于丙烷脱氢制丙烯。然而，高反应温度通常会诱导金属种类的严重烧结和团聚，从而导致催化剂的快速失活。在此，使用重结晶法制备了封装在中空结构硅石-1 （指定为 PtIn@S1-H） 中的 PtIn 纳米团簇 （NCs）。这种材料在丙烷脱氢中表现出很高的催化性能。丙烷转化率和丙烯选择性在 547 °C 下至少在 167.6 小时内分别达到 ∼45-47.5% 和 ∼99%。因此，它对 C₃H₆ 形成的比活性 （0.37–0.59 s^–1） 明显高于 Pt@S1、Pt@S1–H 和其他已报道的基于 Pt 的催化剂。值得注意的是，当进料纯丙烷时，其催化性能保持良好超过 3600 小时，丙烷转化率约为 31-34%，丙烯选择性为 ∼91-95%。更有趣的是，这种催化剂可以通过再生来重复使用。EXAFS、HAADF-STEM 和 DFT 计算以及 AIMD 模拟结果表明，中空结构硅石-1 晶体形貌不仅促进了 Pt₅In₃ 合金 NCs 的形成，还抑制了 NC 的聚集和生长。如果认为催化剂在丙烷转化率降低 15% 时失活，则 PtIn@S1-H 的 TON ≥ 38996，而 PtIn@S1、PtSn@S1、PtSn/Al₂O₃ 和 PtIn/Al₂O₃ 分别获得 5367、4928、798 和 542。 这是因为 In 合金化成 Pt NCs 削弱了 C₃H₇* 中间体与金属 Pt NCs 的相互作用以及 C₃H₆ 在催化剂表面的吸附，从而抑制了 C₃H₇* 裂解反应，增强了丙烷活化和丙烯选择性。