Preparation And Catalytic Property Study Of Catechol-Formaldehyde Resin Stabilized Palladium Nanohybrid Magnetic Microspheres

Phenolic resin is more widely used in industrial production,biomedicine,catalysis and other fields than other polymer resin systems,because of its low cost,simple preparation method and easy surface functionalization.In recent years,new breakthroughs and advances have been made in the research of phenolic resins.Especially,under base conditions people have successfully prepared many nanoscale microsphere hybrid systems based on the phenol formaldehyde resin,resorcinol formaldehyde resin and magnetic core-shell structure phenolic resin,which surface could be used as the effective supports of metal nanopartiles.These nanohybrid materials have important application value in many fields including biomedicine and catalysis.Based on above background,in this thesis the catechol with stronger coordination ability was chosen as the substrate for condensation with formaldehyde to prepare catechol-formaldehyde resin（CFR）microsphere under base conditions.Magnetic Fe₃O₄ nanoparticles and metal nanoparticles could be easily integrated into the CFR spheres by the strong coordination of o-hydroxyl groups to construct magnetic nanohybrid catalysts for dye degradation and organic catalytic reaction.The main contents of this thesis include the following two parts.In the first part,we successfully synthesized catechol-formaldehyde resin（CFR）microsphere in the mixed solvent of water and ethanol under alkaline conditions by a facile solvothermal method,and studied the effect of the concentration of individual component,temperature and the ratio of different solvents on the size and morphologies of as-prepared CFR microspheres.The results showed that the size of CFR microspheres can be controlled between 90 nm and 800 nm,and there is a significant difference in the morphology of the CFR microspheres under different conditions.In the second part,the magnetic Fe₃O₄@CFR core-shell nanospheres were constructed via a facile and controllable hydrothermal route.The shell thickness of Fe₃O₄@CFR nanospheres can be readily tuned by changing the reaction parameters.Especially,the catechol groups on the surface of nanospheres also play a significant role of mussel-inspired chemistry to further combine with graphene oxide（GO）to wrap the Fe₃O₄@CFR spheres.The obtained Fe₃O₄@CFR and Fe₃O₄@CFR@GO nanospheres can be used as the effective catalyst supports of Pd nanoparticles（NPs）.The as-fabricated Fe₃O₄@CFR@PdNPs and Fe₃O₄@CFR@GO@PdNPs nanohybrid catalysts had excellent dispersibility and stability.We studied the catalytic activity of Fe₃O₄@CFR@PdNPs and Fe₃O₄@CFR@GO@PdNPs for different organic reactions including the reduction of methylene blue（MB）and nitrophenols,and Suzuki cross-coupling reaction.The results showed that the both nanocatalysts exhibited super active catalytic activity in the reduction of MB and the Suzuki coupling reaction.In addition,Fe₃O₄@CFR@PdNPs and Fe₃O₄@CFR@GO@PdNPs nanohybrid catalysts are very easy to carry out in separation and recycling due to the presence of magnetic Fe₃O₄ nanoparticles.The results indicated that these nanocatalysts could be successfully reused and exhibited an efficient catalytic performance after recycling five times with a super high conversion（>96%）.In summary,the as-fabricated CFR sphere stabilized Pd nanohybrid magnetic materials in this work will have potential application value in the field of industrial production and catalysis.