负载贵金属纳米颗粒微球制备及催化性能研究

发布时间：2018-03-13 05:10

  本文选题：气溶胶　切入点：负载贵金属颗粒微球　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：负载贵金属颗粒微球能够很好的综合贵金属催化剂独特的物化性能以及颗粒微球载体的优势,因此赋予了负载贵金属颗粒微球较多新的优异性能：贵金属活性组分高度分散,活性催化组分与载体之间的强相互作用,材料良好的的化学以及催化稳定性能,成本低廉等,因此在环境保护,石油化工,新能源等领域具有较高的应用价值。本论文主要用气溶胶一步法合成负载贵金属催化剂的多孔微球并考察了它们的液相反应催化性能,主要研究内容如下：本论文采用气溶胶一步法合成了Fe304@C-Si0：磁性核壳微球,其中Fe3O4为核,壳层为C-SiO2结构,将该核壳微球作为模板合成Fe3O4@C-SiO2@ RF-COOH颗粒微球,(RF-COOH:树脂),随后经高温石墨化、NaOH腐蚀等阶段得到最终产品C-C@Fe3O4磁性多孔微球,并且在该反应过程中,模板Fe3O4@C-SiO2核壳微球的Fe3O4核分裂成更小粒径并均匀分散到C-C@Fe3O4颗粒微球的外层介孔碳中,因此该微球的磁性得到很大的增强(磁性强度由2.4 emu/g增大到11.0 emu/g),提高近四倍之多。C-C@Fe3O4颗粒微球可作为Pt的理想载体,则得到可回收再利用的C-C@Fe3O4-Pt磁性微球,并探究了该微球催化还原对硝基苯酚(4-NP)至对氨基苯酚(4-AP)的性能。结果发现C-C@Fe3O4-Pt微球催化还原4-NP性能优异,并且可通过外加磁场可将C-C@Fe3O4-Pt微球实现快速有效回收,同时5次循环反应后微球催化效率仍达99%以上。为了继续体现用气溶胶法制备负载贵金属颗粒微球的优势,采用一步水热法合成出粒径均匀、分散性好的M@RF-COOH (M:Pt、Au或者Au/Pt合金)纳米微球,其中颗粒微球的粒径和贵金属纳米颗粒的组分可以调控,然后以M@RF-COOH微球为模板利用气溶胶一步法将贵金属颗粒嵌入介孔二氧化硅微球载体中,随后煅烧去掉树脂,最终得到M@Si02颗粒微球,并研究了其催化还原4-NP的性能。结果发现形成贵金属核壳结构的Au/Pt@SiO2, Pt@SiO2微球的催化性能为其他微球的9-14倍,并且5次循环反应后核壳结构的贵金属活性组分以及高度有序的二氧化硅介孔保存完整,显现出其优异的催化稳定性。为了进一步拓展负载贵金属颗粒微球催化液相反应的范围,采用水热法制备出粒径均匀的RF-COOH微球,然后以该微球为载体,通过浸渍还原法得到HRF-COOH-Pt微球。该颗粒微球用来催化氨硼烷(AB)水解,结果表明：HRF-COOH-Pt微球催化AB水解性能优异,其中在30℃下RF-COOH-Pt (6mL K2PtCl6)微球在约80s的时间内催化10mL3.5mg/mL的AB溶液水解彻底,测得还原反应活化能Ea为37.88 kJ/mol。微球经过5次循环后,其催化性能没有衰减。
[Abstract]:The loaded noble metal particle microspheres can well integrate the unique physical and chemical properties of noble metal catalysts and the advantages of the particle microspheres carrier. Therefore, the loaded noble metal particle microspheres have many new and excellent properties: the noble metal active components are highly dispersed. Strong interaction between active catalytic components and carriers, good chemical and catalytic stability of materials, low cost, etc., therefore in environmental protection, petrochemical, In this thesis, porous microspheres supported on noble metal catalysts were synthesized by aerosol one-step method and their catalytic properties of liquid phase reaction were investigated. The main contents of this paper are as follows: in this paper, the Fe304C-Si0: magnetic core-shell microspheres were synthesized by a one-step aerosol method, with Fe3O4 as the core and the shell as the C-SiO _ 2 structure. The core-shell microspheres were used as templates to synthesize Fe3O4C-SiO2 @ RF-COOH microspheres and RF-COOHH: resin. After high temperature graphitization and NaOH corrosion, the final product C-CCOO4 magnetic porous microspheres were obtained. The Fe3O4 nuclei of the template Fe3O4@C-SiO2 core-shell microspheres were split into smaller particles and dispersed evenly into the outer mesoporous carbon of the C-C Fe3O4 microspheres. Therefore, the magnetic properties of the microspheres were greatly enhanced (the magnetic intensity of the microspheres increased from 2.4 emu/g to 11.0 emu / g / g, and the increase of the magnetic intensity was nearly four times. C-Cr Fe _ 3O _ 4 microspheres could be used as ideal support for Pt, and a recoverable C-C _ C _ 3O _ 4-Pt magnetic microspheres were obtained. The catalytic reduction of 4-NP from p-nitrophenol to p-aminophenol (4-APP) by the microsphere was studied. The results showed that the catalytic reduction of 4-NP by C-CC@ Fe3O4-Pt microspheres was excellent, and C-CFe3O4-Pt microspheres could be recovered quickly and effectively by applying magnetic field. At the same time, the catalytic efficiency of the microspheres is still over 99% after five cycles. In order to continue to reflect the advantage of the aerosol method in preparing the loaded noble metal particle microspheres, the particle size of the microspheres prepared by one step hydrothermal method is uniform. The size of the particles and the composition of the noble metal nanoparticles can be controlled. Then, using M@ RF-COOH microspheres as template, the noble metal particles were embedded into mesoporous silica microspheres by one step aerosol method, and then the resin was removed by calcination, and finally the M@ Si02 microspheres were obtained. The catalytic reduction of 4-NP was studied. The results showed that the catalytic performance of au / Pt Sio _ 2 and Pt@SiO2 microspheres was 9-14 times higher than that of other microspheres. After five cycles, the active components of the core and shell structure and the highly ordered mesoporous silica were preserved intact. In order to further expand the range of liquid phase reaction catalyzed by loaded noble metal particle microspheres, RF-COOH microspheres with uniform particle size were prepared by hydrothermal method, and then the microspheres were used as the carrier. HRF-COOH-Pt microspheres were prepared by impregnation reduction method. The particle microspheres were used to catalyze the hydrolysis of ABB. The results showed that the catalytic activity of the HRF-COOH-Pt microspheres on AB hydrolysis was excellent, and the RF-COOH-Pt 6mL K2PtCl6 microspheres were hydrolyzed thoroughly in 10 mL L 3.5mg / mL AB solution at 30 鈩，

本文编号：1604941