Modification And Templating Behavior Of Long-Chain Ionic Liquid In The Synthesis Of PMMA/Pt Microspheres And Pt-Embedded Porous Silica

In this thesis,polymer/Pt composite microspheres were firstly synthesized by using long-chain ionic liquid（LILs）as modifier to construct a bridge connector between polymer microspheres and Pt nanoparticles（PtNPs）.Secondly,ordered Pt-embedded bimodal porous silica was prepared by using polymer/Pt microspheres as macroporous template and LILs as mesoporous template.Finally,ordered Pt-Fe₃O₄-embedded mesoporous silica can be synthesized by using LILs as template.Their content is showed in the following three aspects.1.PMMA/LIL16 microspheres can be obtained by modification of PMMA microspheres using long-chain ionic liquid,1-hexadecyl-3-methylimidazolium chloride（LIL16）as modifier.The characterization of SEM,TEM,electrophoresis experiments and adsorption experiments for anionic dyes confirms that the PMMA/LIL16 microspheres possess high positive surface charge（+117 mV）.PMMA/LIL16/（2 nm）PtNPs@Cit.microspheres with core-shell structure and close-packed PtNPs@Cit on the PMMA/LIL16 microspheres were prepared via an assembly of electronegative citrate-capped PtNPs@Cit（2 nm）on the surface of PMMA/LIL16 microsphere under the condition of(m（PtNPs）/m（PMMA/LIL16）ratio of 6% by means of electrostatic adsorption.PtNPs@Cit.with 10 nm and low negative charge were adsorbed on the PMMA/LIL16 microspheres by way of sporadic and discrete distribution of PtNPs@Cit..PMMA/LIL16@（2 nm）PtNPs composite microspheres with dispersive distribution of PtNPs（2 nm）on PMMA/LIL16 microspheres were obtained through an electrostatic adsorption assembly of PtCl62-on the surface of PMMA/LIL16 and subsequently in situ reduction.PMMA/（2 nm）PtNPs@LIL16 microspheres with monodisperse PtNPs@LIL16 adsorbed on the surface of PMMA microspheres can be prepared by an electrostatic adsorption assembly of electropositive LIL16-stabilized PtNPs@LIL16（2 nm）on the unmodified PMMA microspheres.2.Pt-embedded ordered bimodal porous silica was synthesized by a sol-gel process under acidic condition using PMMA/LIL16/（2 nm）PtNPs@Cit.microspheres as macroporous template,LIL16 as mesoporous template,and tetraethylorthosilicate（TEOS）as the silica source.The influences of particle size,mixed proportion,synthesized method and calcination temperature on the structure of the Pt-embedded ordered bimodal porous silica were investigated.The measurements of small-angle XRD,TEM and nitrogen sorption experiment show that the Pt-embedded ordered bimodal porous silica possess spherical macropores with PtNPs（11 nm）embedded within the inwall of the macropores,and the wall of the macropores consists of long-range ordered hexagonal mesoporous silica（SBA-3 type）channels with average pore size of 2.636 nm.The BET surface area of the Pt-embedded ordered bimodal porous silica is 984.50 m2/g.Pt-embedded ordered bimodal porous silica can be also formed using PMMA/LIL16@（2 nm）PtNPs or PMMA/（2 nm）PtNPs@LIL16 microspheres as macroporous template and LIL16 as mesoporous template.However,the particle sizes of PtNPs within the voids of macropores have a large change.Compared with the electroless polymerization of aniline without catalyst,the Pt-embedded ordered bimodal porous silica have obvious catalytic performance.3.Pt-Fe₃O₄-embedded ordered mesoporous silica has been synthesized via a hydrothermal synthesis procedure under basic synthesis medium using LIL16 as template and TEOS as the silica source in the mixed dispersion of PtNPs@Cit.and Fe₃O₄@SDS/LIL16（using sodium dodecyl sulfate（SDS）and LIL16 as primary and secondary modifying layer,respectively）.The tests of small-angle XRD,TEM and nitrogen sorption experiment indicate that the composite mesoporous silica（Pt-Fe₃O₄@MCM-41）has a long-range ordered hexagonal mesoporous structure（MCM-41 type）with average pore size of 3.058 nm and PtNPs or Fe₃O₄NPs（¹0 nm）dispersed randomly in the mesoporous network.The BET surface area of the Pt-Fe₃O₄@MCM-41 is 1067.55 m2/g.The Pt-Fe₃O₄@MCM-41 was used as an adsorbent to adsorb rhodamine B and methylene blue from the dye solutions,as a catalyst in the catalytic reaction of electroless polymerization of aniline.It was found that the Pt-Fe₃O₄@MCM-41 displays a highly adsorptive performance and decolorization rate for both rhodamine B and methylene blue,and shows a certain catalytic capacity compared with the reaction without catalyst.Moreover,after adsorption procedure and catalytic reaction,the Pt-Fe₃O₄@MCM-41 can be rapidly separated from the solution under a magnet,indicating a good magnetic response and separation characteristics.