Functionalization Of Nanometallic Organic Frameworks And Their Catalytic Applications

Metal organic framework（MOF）materials are widely used in catalysis because they combine the advantages of homogeneous and homogeneous catalysts;highly homogeneous and tunable pore structures;high porosity and surface area for substrate enrichment;pore space providing a special catalytic microenvironment;and structural tunability allowing the synthesis of post-modification active sites.In addition,the most important feature of MOFs is their structural tunability,which greatly broadens their applications in various fields.Due to the versatility of MOFs and their highly coordinated composition and structure,hollow structures can be designed and constructed to further enhance the efficient performance of MOFs.In this thesis,we synthesized functionalized MOF composite catalysts by two strategies and successfully applied them in tandem catalytic reactions and selective hydrogenation reactions.First,we successfully synthesized a series of MIL-101（Fe）derivatives by exploring the experimental conditions using a one-pot method.The effect of their different functional groups on the lewis acidity of Fe in MIL-101（Fe）nodes was investigated;the catalytic activity of MIL-101（Fe）-X was probed for Knoevenagel reactions with different substrates,and the reactivity order of MIL-101-X was closely related to the ability of electron-absorbing effect.MIL-101-NO₂ with the strongest electron-absorbing group showed good conversion at low temperatures.The versatility of the electron effect on the catalytic activity is confirmed and brings the possibility to tune the activity of MOFs by introducing organic ligands with different functional groups.Secondly,we successfully synthesized MIL-101（Fe）with uniform octahedral morphology in size by a simple method,and then impregnated the precious metal Pt by a two-solvent method to obtain Pt@MIL-101（Fe）with yolk-shell after reduction,and the size of the second layer of Pt nanoparticles could be controlled by adjusting the concentration of the precursor Pt salt.The catalysts showed good activity and selectivity for the selective catalytic hydrogenation reaction of nitrobenzene derivatives,and the product selectivity was significantly higher than that of the conventional loaded catalysts.