Imparting functionality to a metal–organic framework material by controlled nanoparticle encapsulation

Abstract

Microporous metal-organic frameworks (MOFs) that display permanent porosity show great promise for a myriad of purposes. The potential applications of MOFs can be developed further and extended by encapsulating various functional species (for example, nanoparticles) within the frameworks. However, despite increasing numbers of reports of nanoparticle/MOF composites, simultaneously to control the size, composition, dispersed nature, spatial distribution and confinement of the incorporated nanoparticles within MOF matrices remains a significant challenge. Here, we report a controlled encapsulation strategy that enables surfactant-capped nanostructured objects of various sizes, shapes and compositions to be enshrouded by a zeolitic imidazolate framework (ZIF-8). The incorporated nanoparticles are well dispersed and fully confined within the ZIF-8 crystals. This strategy also allows the controlled incorporation of multiple nanoparticles within each ZIF-8 crystallite. The as-prepared nanoparticle/ZIF-8 composites exhibit active (catalytic, magnetic and optical) properties that derive from the nanoparticles as well as molecular sieving and orientation effects that originate from the framework material.

Photoreduction of CO2 on ZIF-8/TiO2 nanocomposites in a gaseous photoreactor under pressure swing

“…The TiO2 (P25) was consequently modified by adding a thin layer of microporous zeolitic imidazolate framework (ZIF-8) to form a core-shell structure. The selection of ZIF-8 shell was based on the considerations of providing excellent CO2 capture capacity and water tolerance [19], and protecting further oxidation of the synthesized products as it exhibited a high cut off ratio for CH4 to CO2 [20]. The ZIF-8/TiO2 core-shell nanocomposite was fabricated using a step-by-step self-assembly method (more details in supporting information).…”

In situ X-ray diffraction monitoring of a mechanochemical reaction reveals a unique topology metal-organic framework

“…Due to its high porosity and excellent resistance to pressure, temperature and steam, ZIF-8 has been extensively studied for applications in carbon sequestration and is also one the four metal-organic frameworks being manufactured commercially (Basolite Z1200) [17][18][19][20][21][22][23][24][25] . Crystallization of ZIF-8 from solution has been explored by several groups 26,27 , and a non-porous polymorph of ZIF-8 with a diamondoid (dia) topology was recently reported 28,29 .…”

Metal-Organic Frameworks for Catalysis

“…Different synthetic routes towards the formation of Au@Ag/ZIF-8 and Au@AuAg/ZIF-8, respectively [79] 液相浸渍法可以得到各种金属和 MOFs 的复合物, incorporated into MIL-101 and the subsequent tandem catalysis of the dehydrogenation of ammonia borane and hydrogenation of nitro compounds [82] 为了降低贵金属消耗, 同时提高催化反应效率, [83] Figure 10 Synthesis of Pd@Co@MIL-101, Pd@Co/MIL-101, and PdCo@MIL-101 catalysts by different procedures and reducing agents [83] 性比 Figure 12 Schematic illustration of the controlled encapsulation of nanoparticles in ZIF-8 crystals [87] 通过在纳米颗粒外围形成 MOFs 的超结构来实现包 覆, 形成 core-shell 或 yolk-shell 结构, 也是一种重要的 策略和方法. Tsung 等 [88] 通过牺牲模板法生成了 Pd 纳米 Figure 13 Growth procedure for the nanocrystal@ZIF-8 yolk-shell nanostructures [88] 利于催化反应底物 Figure 14 Schematic illustration of the synthesis of Co-CoO@N-doped porous carbon nanocomposites via the pyrolysis of ZIF-67 [91] 3 MOFs 的光催化 MOFs 结构中的金属簇被认为可以扮演半导体量子 点的角色, 同时其有机配体基于"天线效应", 在光激 发条件下用来活化这些金属簇 [92,93] , 从而使得 MOFs 成 为可能的光催化剂, 并用于光催化反应.…”