Metallic nanoparticles immobilized in magnetic metal–organic frameworks: preparation and application as highly active, magnetically isolable and reusable catalysts
作者:Hai-juan Zhang、Sheng-da Qi、Xiao-ying Niu、Jing Hu、Cui-ling Ren、Hong-li Chen、Xing-guo Chen
DOI:10.1039/c4cy00072b
日期:——
Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this paper, ultrafine noble metallic nanoparticles are incorporated into cauliflower-like porous magnetic metalâorganic frameworks (MOFs). With the restriction effects of the pore/surface structure in the MOFs, âsurfactant-freeâ metallic nanoparticles are successfully obtained on a 2â3 nm scale. In addition, both the thickness of MOFs shell and the content of noble metallic NPs are tunable on the MOFs coating. Moreover, the microspheres exhibit excellent performance for the catalytic reduction of p-nitrophenol with a turnover frequency of 3094 hâ1. The uniform cavities in the MOFs shell provide docking sites for p-nitrophenol and act as confinement nanoreactors, which greatly improves the catalytic performance. Most importantly, the magnetically responsive microspheres can be easily recovered by a magnetic field and show excellent reusability. The as-prepared catalyst also shows good activity for the reduction of other nitrobenzenes. Consequently, this work provides a highly active, magnetically isolable, and recyclable catalyst, which can be used for various catalytic industrial processes. The fundamental model can be further employed in a variety of biomedical fields including drug delivery and biological molecules separation.
催化反应后催化剂的分离和回收对于降低催化剂成本以及避免工业应用中产生废物至关重要。本文将超细贵金属纳米颗粒嵌入到花椰菜状的多孔磁性金属-有机框架(MOFs)中。由于MOFs的孔隙/表面结构的限制作用,成功制备了2-3 nm尺度的“无表面活性剂”金属纳米颗粒。此外,MOFs涂层的厚度以及贵金属NPs的含量均可调节。并且,微球在催化对硝基苯酚还原反应中表现出优异的性能,其催化转化频率高达3094 h⁻1。MOFs壳层中的均匀空腔为对硝基苯酚提供了结合位点,并作为限制纳米反应器,极大地提高了催化性能。最重要的是,磁响应微球可以通过磁场轻松回收,并显示出优异的重复使用性。所制备的催化剂对其他硝基苯的还原也表现出良好的活性。因此,这项工作提供了一种高度活性、可磁性分离和可循环利用的催化剂,可用于各种催化工业过程。这一基本模型还可以进一步应用于包括药物输送和生物分子分离在内的多种生物医学领域。