The Fischer–Tropsch synthesis (FTS) reaction is widely used to produce clean hydrocarbon fuels or chemicals. The key challenge for FTS is the control of product distributions. Herein, iron was employed as the active species, and the supported (Fe/S1 and Fe/S2) and encapsulated (Fe@S1 and Fe@S2) catalysts with pure siliceous zeolite were successfully prepared by incipient wetness impregnation and solvent-free hydrothermal method, respectively. The iron species encapsulated in silicalite zeolite, rather than being present on the surface, enhanced the acidity of zeolite, which was effective in regulating the FTS products. The acidic site can be divided into two types: Lewis and Brønsted, where the Brønsted acid sites are much more stable than Lewis acid sites at FTS reaction temperature. Moreover, Fe@S1 and Fe@S2 with much more Brønsted acid sites displayed a higher selectivity of isoparaffins in the FTS products compared to the supported catalysts (17.6% and 18.6% for Fe@S1 and Fe@S2 vs. 4.1% and 11.8% for Fe/S1 and Fe/S2, respectively). Thus, the acidity of silicalite zeolite can be regulated by encapsulating active metal in it, which is a promising prospect for tuning production distribution in FTS reactions.

中文翻译：

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用于提高 CO 加氢异链烷烃选择性的硅沸石负载铁催化剂

费托合成（FTS）反应广泛用于生产清洁的碳氢化合物燃料或化学品。 FTS 面临的主要挑战是产品分销的控制。本文以铁为活性物质，通过初湿浸渍和无溶剂水热法成功制备了纯硅质沸石负载型（Fe/S1和Fe/S2）和包埋型（Fe@S1和Fe@S2）催化剂。方法，分别。铁物质被封装在硅质沸石中，而不是存在于表面，增强了沸石的酸度，这可以有效调节 FTS 产物。酸性位点可分为两种类型：Lewis 和 Brønsted，其中 Brønsted 酸性位点在 FTS 反应温度下比 Lewis 酸性位点稳定得多。此外，与负载型催化剂相比，具有更多布朗斯台德酸位点的 Fe@S1 和 Fe@S2 在 FTS 产品中表现出更高的异链烷烃选择性（Fe@S1 和 Fe@S2 分别为 17.6% 和 18.6%，而 Fe@S1 和 Fe@S2分别为4.1% 和 11.8%）分别为 Fe/S1 和 Fe/S2 的 %）。因此，硅质沸石的酸度可以通过在其中封装活性金属来调节，这对于调节费托合成反应中的产物分布具有广阔的前景。