Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University , Beijing 100084, P.R. China.
J Am Chem Soc. 2013 Oct 16;135(41):15322-5. doi: 10.1021/ja408624x. Epub 2013 Oct 8.
We report, for the first time, the preparation of novel c-axis oriented ZSM-5 hollow fibers by a combination of seeding and steam-assisted crystallization method using quartz fibers as the temporary soft substrate and Si source. The growth of such unique structure undergoes the development of a b-axis oriented ZSM-5 cylinder, followed by the growth of c-axis oriented ZSM-5 crystals vertically inside the cylinder and then outside the cylinder, by an in situ solid-solid transformation mechanism. The obtained ZSM-5 hollow fibers are composed of pure hierarchical ZSM-5 crystals with high crystallinity, good structural stability, and high surface area and have potential applications for microreactors, separators, and catalysts. The catalytic performance of ZSM-5 hollow fibers is tested in the methanol to gasoline reaction, as an example of their practical application. They exhibit both higher yield of gasoline and far longer lifetime compared to the conventional ZSM-5 due to the improved mass and heat diffusion rate inside the meso-/macropores of c-axis oriented structure.
我们首次报道了一种新型的 c 轴取向 ZSM-5 中空纤维的制备方法，该方法采用石英纤维作为临时软基底和硅源，结合种子法和蒸汽辅助结晶法。这种独特结构的生长经历了 b 轴取向 ZSM-5 圆柱的形成，然后通过原位固-固转变机制，在圆柱内部和外部垂直生长 c 轴取向 ZSM-5 晶体。得到的 ZSM-5 中空纤维由纯分级 ZSM-5 晶体组成，具有高结晶度、良好的结构稳定性和高表面积，在微反应器、分离器和催化剂等方面具有潜在的应用。以甲醇制汽油反应为例，对 ZSM-5 中空纤维的催化性能进行了测试，展示了其实际应用的前景。与传统的 ZSM-5 相比，由于 c 轴取向结构的中/大孔内的质量和热扩散速率得到了改善，ZSM-5 中空纤维的汽油产率更高，寿命更长。
