Synthesis And Properties Of Composites Based On Metal Organic Framework

As a sort of porous material with periodic network structure,metal-organic framework(MOF)is constructed with metal ions or clusters and organic ligands.Due to the adjustable channel structure,abundant unsaturated metal sites and modifiable ligands,MOF has attracted more and more attention in various fields,such as photonics,electronics,magnetism,adsorption,separation,catalysis and so on.In this dissertation,MOF nanocrystals and ultrathin film were synthesized and further employed to fabricate composites by adsorbing nanoparticles(NPs),mixing different metals and being wrapped with porous polymers.We further studied the catalytic performance,stability,absorption property and conductivity of these composites.1.Firstly,we synthesized nano MOF and Pt NPs with uniform size distribution.Then,the MOF@Pt NPs was synthezied by adsorbing Pt NPs onto the surface of MOF.Finally,the second MOF shell was constructed around MOF@Pt NPs to form sandwitch structure.The thickness of MOF shell could be controlled by changing the amount of precursors.This strategy showed good universality and could also be used in other MOFs and noble metal nanoparticles.The sandwitch structure showed better ability to selectively regulate the hydrogenation of α,β-unsaturated aldehydes than traditional supported catalysts.2.The secondly growing MOF shell influenced the diffusion rate of cinnamaldehyde molecule to access Pt NPs,which largely determined the catalytic activity.Most of MOF are hydrophilic porous material and good at adsorbing water.Cinnamaldehyde molecule is conjugated and insoluble in water.In order to keep the selectivity of cinnamaldehyde hydrogenation and increase the adsorbability to reactant,the shell should be constructed by hydrophobic and porous material with abundant unsaturated Fe sites.Therefore we chose conjugated micro-and mesoporous polymers with iron(III)porphyrin as the new shell to fabricate effective and selective catalysts for cinnamaldehyde hydrogenation.3.Bimetal-organic framework(BMOF)is constructed by two different metal ions or clusters and organic ligand.The introduction of second metal can improve the stability and catalytic ability of framework.By introducing Fe into Mn-MOF,the stability and activity of catalyst were improved a lot in the epoxidation of alkene with H2O2 as oxidant.4.Most of MOFs are insulators,so conductive MOFs are attracting more and more attention due to its unique characteristics.Nevertheless,there are many challenges about constructing ultra-large MOF film with controllable thickness.As one of MOFs,metal-organic graphene analogue(MOGA)is conductive and hydrophobic.We designed a new strategy,vapor-induced method(VID),to synthesis a centimeter-sized film and applied stripping method to improve the surface roughness,which opened up a new avenue for application of MOF film in the field of flexible electronics.