【作者】 刘静；

【导师】 姚守拙； 傅迎春；

【作者基本信息】 湖南师范大学 ， 分析化学， 2016， 硕士

【摘要】 磁性纳米粒子(MNPs)具有优异的超顺磁性、生物兼容性、催化性和低毒性等性质,方便制备复合材料,已被广泛应用于分离富集、酶固定化和靶向给药等领域。目前磁性复合材料的制备主要是以磁性材料为核的生长法或磁性材料与其它材料的共混合法,而基于其本身组成制备复合材料的研究鲜有报导。本论文开发了以MNPs为自牺牲模板来制备一系列新型复合材料的新方法,发展了基于新材料的电化学传感及电池技术,效果满意。主要内容如下：1-制备MNPs核@金纳米粒子(AuNPs)-普鲁士蓝(PB)复合壳的复合材料及电化学催化检测过氧化氢。MNPs在含盐酸羟胺和亚铁氰化钾的酸性混合溶液中磁珠表面Fe203与H+反应释放Fe3+并与亚铁氰化钾反应生成PB,氯金酸同时被羟胺还原成AuNPs,生成MNPs@AuNPs-PB复合材料。通过控制反应物的浓度和反应可调控PB-Au纳米复合物的尺寸及形貌。采用扫描透射电镜技术和多种电化学技术对其形貌、电化学性能及催化性能进行表征,并与常规电化学沉积PB修饰电极进行比较。该材料可集成MNPs的磁性、AuNPs导电性和PB的催化性,甚至表现出协同效应,催化和检测灵敏度效果满意。该H202传感器线性检测区间为0.004-22.12 mM,灵敏度为647μA cm-2 mM-1,检测下限低(1.1 nM),并有优异的操作和储存稳定性。2.制备MNPs核@Fe/Pt壳纳米复合材料用于CH3OH和H202的电化学催化。采用硼氢化钠还原磁珠表面Fe203生成Fe,后者将氯铂酸通过置换反应生成Pt,最终生成MNPs核@Fe/Pt壳复合材料。在1M乙醇和0.5 M硫酸溶液中,对比工业催化材料Pt/C,该材料对甲醇催化效果好,抗CO毒化能力强,稳定性好,可望用于高效燃料电池。基于铂对过氧化氢优异的电化学催化效果,实现了对不同浓度的过氧化氢的电化学检测,催化和检测灵敏度效果较满意。3.基于MNPs核@Fe/Pt壳纳米复合材料的多功能磁性搅拌子。通过施加磁场,MNPs核@Fe/Pt壳复合材料沿磁场线排列成链状结构,并随磁场线而运动,形成纳米级搅拌子,促进传质,(动态)增强电催化性能。更多还原

【Abstract】 Magnetic nanoparticles （MNPs） exhibit excellent superparamagnetism, biocompatibility, catalysis ability, low toxicity, feasibility to construct composite materials, and have been broadly applied in various fields including separation/concentration, enzyme immobilization and targeted drug-delivery. Currently, magnetic composite materials are prepared through methods of magnetic core-based growth or mixing of magnetic materials and other species, however, method based on inherent content of magnetic materials is rare. In this thesis, we developed a series of novel methods based on self-sacrificing of MNPs template to prepare nanocomposites for electrochemical sensing and cell with satisfactory performance. The main contents are as follows:1. Preparation of magnetic nanocomposites of MNPs core@Au nanoparticles （AuNPs）-Prussian blue （PB） composite shell for electrochemical catalysis of H₂O₂. In an acidic solution containing K4Fe（CN）6, HAuCl4 and NH2OH·HCl, MNPs release Fe3+ to react with K4Fe（CN）6 to form highly electrochemically active PB, which is accompanied with reduction of HAuCl4 to form AuNPs, finally yielding MNPs@AuNPs-PB Composites. The concentration of K3Fe（CN）6 and reaction time were optimized. By controlling the concentration of the reactants and reaction time, we could regulate the size and morphology of the nanocomposites. Scanning transmission electron microscope and a variety of electrochemical techniques were used to characterize the morphology, electrochemical properties and catalytic properties. The materials integrated magnetism of MNPs, conductivity of AuNPs and catalytic ability of PB, even exhibited synergistic effects. the composites film showed higher electro-catalytic ability to the reduction and oxidation of H₂O₂ than those based on conventional PB, with a linear detection range for H₂O₂ from 0.004 to 22.12 mM, a sensitivity of 647 μA·cm-2·mM-1, and a limit of detection of 1.1 nM.2. Preparation of MNPs core@Fe/Pt shell nanocomposites for electrochemical catalysis of methanol and H₂O₂. Sodium borohydride was added to react with bead surficial Fe2O3 of MNPs to generate a thin film of Fe, which is subjected to replacement reaction with platinum salt to generate Pt, finally yielding MNPs@Fe/Pt composites. In a mixed solution of 1 M ethanol and 0.5 M sulfuric acid, the composites showed superior catalysis and anti-poisoning abilities as well as stability, comparing with industrial Pt/C catalyst, which could be promising for efficient fuel cell. Secondly, based on the excellent electrochemical catalytic effect of platinum to hydrogen peroxide, the nanocomposites were tested for electrochemical detection of hydrogen peroxide with satisfactory performance.3. Multifunctional magnetic nano-stirrer based on MNPs@Fe/Pt composites. In a magnetic field, the MNPs@Fe/Pt composites arranged along the magnetic line and form magnetic chains, which could move along with the movement of magnetic field. Based on above concept, we developed the magnetic chains as nano-stirrer to enhance the catalysis performance of methanol and hydrogen peroxide.更多还原