Khosroshahi Negin, Doaee Samira, Safarifard Vahid, Rostamnia Sadegh
Department of Chemistry, Iran University of Science and Technology, Tehran, 16846-13114, Iran.
Heliyon. 2024 May 14;10(10):e31254. doi: 10.1016/j.heliyon.2024.e31254. eCollection 2024 May 30.
In metal-organic frameworks (MOFs), confined space as a chemical nanoreactor is as essential as coordinatively unsaturated metal site catalysis. The properties of MOFs can be adjusted through the incorporation of functional groups and open metal sites in frameworks that can modify the catalytic performance. In this regard, a set of defect-engineered MOFs, Ex-MOF-808(NH, NO, H) and Mix-MOF-808(NH, NO, H), were synthesized by ultrasonic-assisted linker exchange approach (Ex-MOFs) and solvothermal mixing ligand method (Mix-MOFs), respectively. Further, the relationship between the preparation method, structural properties, and catalytic efficiency of the prepared materials in the selective oxidation of methyl phenyl sulfide (MPS) has been investigated. By analyzing zeta potential, it was found that in the exchange method, the amount of defect and functional groups on the surface of MOFs are more than in the mixing method, which also affects the catalytic activity. In our contribution, mix-MOF-808(NO) carrying nitro groups at their organic linkers, which has a well-dispersion of nitro groups at the framework exhibits selective conversion of MPS to sulfone (91 %). Furthermore, the performance of stable heterogeneous catalysts was investigated for three cycles, which demonstrated their great potential for advanced catalytic oxidation.
在金属有机框架材料（MOFs）中，作为化学纳米反应器的受限空间与配位不饱和金属位点催化同样重要。MOFs的性质可通过在框架中引入官能团和开放金属位点来调节，这些官能团和金属位点能够改变催化性能。在这方面，分别通过超声辅助连接体交换法（Ex-MOFs）和溶剂热混合配体法（Mix-MOFs）合成了一组缺陷工程化的MOFs，即Ex-MOF-808(NH, NO, H)和Mix-MOF-808(NH, NO, H)。此外，还研究了所制备材料在苯甲硫醚（MPS）选择性氧化反应中的制备方法、结构性质与催化效率之间的关系。通过分析zeta电位发现，在交换法中，MOFs表面的缺陷和官能团数量比混合法中的更多，这也影响了催化活性。在我们的研究中，在其有机连接体上带有硝基的Mix-MOF-808(NO)，在框架中硝基分布均匀，能将MPS选择性转化为砜（91%）。此外，还对稳定的多相催化剂的性能进行了三个循环的研究，结果表明它们在高级催化氧化方面具有巨大潜力。
