Preparation And Catalytic Application Of Magnetic-Noble Metal Nanocomposites

With the unceasing research and development of Nanotechnology,nanocomposite has attracted more and more attention,among which,Fe₃O₄-Au nanocomposite,with catalytic activity of noble metal nanoparticles has become potent material in chemical reactions with CO in low temperature,alcohol catalysis,catalytic hydrogenation,etc.This kind of Nanocomposite catalyst,combined with high efficient separation characteristics of Fe₃O₄ when it is in external magnetic and high catalytic activity of gold nanoparticles,both make the separation and recovery of noble metal nanoparticles easier and effectively prevent the agglomeration of noble metal nanoparticles,which ensures it good catalytic activity and longer service life.In particular,Using magnetic nanocomposite particles with core-shell structure as gold nanoparticle carrier is more suitable.The shell of core-shell structure effectively prevents the agglomeration and oxidation of Fe₃O₄ and provides space Available for modification,which helps to supported gold nanoparticles.In this condition,this paper carries out the following work on the preparation and characterization of magnetic-metal nanocomposites and catalytic organic pollutants.?1?Solvothermal method are adopted to prepare Fe₃O₄ particles to explore how surfactant at different systems affects the synthesis of nano-sized particles and select out surfactants ethylenediamine and Fe₃O₄ nanoparticles compounded with sodium citrate as the surfactant nanoparticles to coat PANI as a further step.?2?Respectively explore the how Fe₃O₄,temperature,solvent particles influence the preparation of Fe₃O₄@PANI.The outcome is that ethylenediamine Fe₃O₄@PANI reunionis the most obvious one and Fe₃O₄@PANI of sodium citrate system not only has a good dispersibility,but it also even in shell,therefore,the latter should be the better choice.Meanwhile,in ice-water bath,with water as the solvent,it helps to form a even shell.While in room temperature,with mixed solvent of ethanol or water,it produces aniline oligomers resembles flocculence which hinders to coat an even PANI shell.?3?Prepare Fe₃O₄@PANI@Au magnetic nanocomposites via different methods and compare their difference in effect.The outcome is that,materials prepared with one-pot synthesis and in-situ reduction is not fit for catalyst.Therefore,this paper designs and constructs Fe₃O₄@PANI@Au magnetic properties nanocomposites of three-layer structure: core-shell-shell,and apply it in the catalysis and degradation process of 4-nitrophenol and Methylene blue,Methyl orange,Congo red,Rhodamine B.Catalytic results shows that,this catalyst can effectively and quickly catalyze and degrade these five kinds of organic pollutants,and it has excellent function in generality,repeated utilization and stability.