State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology , Dalian 116024, China.
ACS Appl Mater Interfaces. 2018 Jan 31;10(4):4151-4160. doi: 10.1021/acsami.7b17568. Epub 2018 Jan 22.
Up to now, the fabrication of well-intergrown Co-based zeolitic imidazolate framework (ZIF) membranes on porous tubular supports is still a major challenge. We report here a heteroepitaxial growth for preparing well-intergrown Co-based ZIFs (ZIF-67 and ZIF-9) tubular membranes with high performance and excellent thermal stability by employing a thin layer of ZnO nanorods acting as both nucleation centers and anchor sites for the growth of metal-organic framework membranes. The results show that well-intergrown Co-ZIF-67 and Co-ZIF-9 membranes are successfully achieved on the ZnO nanorod-modified porous ceramic tubes. This highly active heteroepitaxial growth may be attributed to the fact that the (Zn,Co) hydroxy double salt intermediate produced in situ from ZnO nanorods acts as heteroseeds and enables the uniform growth of Co-based membranes. The H/CO selectivity of the as-prepared Co-ZIF-9 tubular membrane could reach about 23.8 and the H/CH selectivity of Co-ZIF-67 tubular membrane is as high as 45.4. Moreover, the membranes demonstrate excellent stability because of the ZnO nanorods as linkers between the membrane and substrate.
到目前为止，在多孔管状载体上制备具有良好结晶度的钴基沸石咪唑骨架（ZIF）膜仍然是一个主要挑战。我们在此报告了一种异质外延生长方法，通过在薄的氧化锌纳米棒层上，将其作为核化中心和金属有机骨架膜生长的锚定点，制备具有高性能和优异热稳定性的钴基 ZIF（ZIF-67 和 ZIF-9）管状膜。结果表明，在 ZnO 纳米棒修饰的多孔陶瓷管上成功制备了具有良好结晶度的 Co-ZIF-67 和 Co-ZIF-9 膜。这种高活性的异质外延生长可能归因于 ZnO 纳米棒原位生成的（Zn，Co）羟盐中间相作为异质晶种，实现了 Co 基膜的均匀生长。所制备的 Co-ZIF-9 管状膜的 H/CO 选择性可达到约 23.8，Co-ZIF-67 管状膜的 H/CH 选择性高达 45.4。此外，由于 ZnO 纳米棒作为膜和基底之间的连接物，膜表现出优异的稳定性。
