A facile synthesis route, named dual-layer crystal growth method, was developed for preparing Pd-based zeolite capsule catalyst. The millimeter-sized zeolite capsule catalyst (Pd/SiO₂-SZ) with a core-shell structure was prepared by a developed dual-layer crystal growth method: coating Silicalite-1 and H-ZSM-5 zeolite orderly as double shells encapsulating the Pd/SiO₂ core catalyst. We employed the prepared Pd/SiO₂-SZ zeolite capsule catalyst for the direct synthesis of liquefied petroleum gas (LPG) from syngas (CO + H₂). In the reaction, the zeolite capsule catalyst showed excellent LPG selectivity than the single core catalyst of Pd/SiO₂ and the physical mixture catalyst prepared by a simply mixing core and shell catalysts. The Pd/SiO₂-SZ realized the highest LPG selectivity of 34.4% with CO conversion of 14.1%. Moreover, the optimal reaction temperature and pressure in the reaction for LPG direct synthesis from syngas over Pd/SiO₂-SZ catalyst were 623 K and 5.0 MPa, respectively. The high performance of zeolite capsule catalyst Pd/SiO₂-SZ was attributed to the enforced mass transfer diffusion from inside to outside of the catalyst.

开发了一种简便的合成路线，称为双层晶体生长方法，以制备Pd基沸石胶囊催化剂。通过开发的双层晶体生长方法制备了具有核-壳结构的毫米大小的沸石胶囊催化剂（Pd / SiO ₂ -SZ）：将Silicalite-1和H-ZSM-5沸石有序地涂覆为双层壳，将其包裹Pd / SiO ₂核心催化剂。我们将制备的Pd / SiO ₂ -SZ沸石胶囊催化剂用于从合成气（CO + H ₂）直接合成液化石油气（LPG ）。反应中，与Pd / SiO ₂单核催化剂相比，沸石胶囊催化剂具有优异的LPG选择性。通过简单地将核和壳催化剂混合而制备的物理混合物催化剂。Pd / SiO ₂ -SZ实现了34.4％的最高LPG选择性，CO转化率为14.1％。此外，在Pd / SiO ₂ -SZ催化剂上由合成气直接合成LPG的最佳反应温度和压力分别为623 K和5.0 MPa。沸石胶囊催化剂Pd / SiO ₂ -SZ的高性能归因于从催化剂内部到外部的强制传质扩散。