设计了一种具有蛋黄-壳结构的新型催化剂,以克服多相催化中贵金属的浸出问题。通过模板方法,钯(Pd)纳米颗粒被由2,4,6-三羟基苯-1,3,5-三甲醛(Tp)和对苯二胺(Pa)组成的中空球形共价有机框架(COF)封装。具有蛋黄-壳结构的最终催化剂表示为(Pd/C)@TpPaCOF。通过透射电子显微镜(TEM)证实了这种新型复合材料(Pd/C)@TpPaCOFs的独特形态和化学结构,激光粒子分析仪,X射线衍射(XRD)和N2吸附和解吸。随后,为了展示其结构设计带来的催化性能,该新型催化剂用于催化Suzuki反应。有趣的是,该催化剂对芳基苯表现出高达100%的明亮尺寸截止效率,并且仅在0.05mol%Pd负载下实现高转化率。此外,该催化剂可以通过过滤容易地回收并重复使用至少五个连续的循环,而其活性没有任何显著的损失。
A novel catalyst with a yolk-shell structure was designed to overcome the leaching of noble metals in heterogeneous catalysis. Through a template method, palladium (Pd) nanoparticles were encapsulated by hollow spherical covalent organic frameworks (COFs) consisting of 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (Tp) and p-phenylenediamine (Pa). The final catalyst with a yolk-shell structure was denoted as (Pd/C)@TpPa COFs. The unique morphology and chemical structure of this novel composite (Pd/C)@TpPa COFs were confirmed by a transmission electron microscope (TEM), a laser particle analyzer, X-ray diffraction (XRD), and N2 adsorption and desorption. Subsequently, to demonstrate its catalytic performance brought by structural design, this novel catalyst was applied to catalyze the Suzuki reaction. Interestingly, this catalyst exhibited a brilliant size cutoff efficiency for aryl benzene amounting to 100% and achieved a high conversion with only 0.05 mol% Pd loading. Besides, this catalyst could be readily recovered via filtration and reused for at least five consecutive cycles without any significant loss in its activity.