Ag（Pt）基纳米复合材料的牺牲模板法制备及催化和SERS性能

发布时间：2018-04-14 09:02

本文选题：牺牲模板 + 置换反应　；参考：《哈尔滨工业大学》2017年博士论文

【摘要】：纳米材料制备技术的发展已使单一组分均匀地掺入复合材料成为可能,而且不同组分之间的协同作用可以赋予纳米复合材料全新的功能。可控形貌与尺寸贵金属纳米颗粒的制备成为近年来的研究热点,应用涉及光学、传感和电化学等多个领域。高的生产成本、还原反应过程中污染物的引入、纳米颗粒的团聚等问题的存在使贵金属纳米材料的应用和推广受到限制。本论文提出以中间价态过渡金属氧化物(Cu_2O与Mn_3O_4)为牺牲模板制备Ag、Pt纳米复合材料的方法,具有实验条件温和、原子经济等优点,有利于高性能、高纯度贵金属纳米材料的制备。本研究采用中间价态过渡金属氧化物Cu_2O和Mn_3O_4作为贵金属纳米颗粒(Ag、Pt)的还原剂和成核位点,分别制备了Ag/Cu_2O纳米复合材料、Pt/Mn_3O_4-rGO三元复合材料以及Ag/Ag_2S/Ag_3CuS_2三元复合材料,并且将多元贵金属纳米复合材料应用于表面增强拉曼光谱(SERS)的分子检测、可见光催化降解甲基橙和催化氧还原反应(ORR)等多种领域。Cu_2O和Mn_3O_4为牺牲模板与Ag+或Pt4+反应,利用它们之间的电位差制备形貌和粒径可控的贵金属纳米复合材料和多元复合材料,特别是在Ag/Cu_2O和Pt/Mn_3O_4-rGO多元复合材料的制备过程中置换反应没有进行彻底,因此纳米复合材料能够保持牺牲模板原有的三维形貌。此种方法制备出的Ag基及Pt基纳米复合材料表面清洁,新颖而均一的微观形貌能够赋予贵金属纳米颗粒更优良的催化和分子检测性能。通过电沉积方法在氧化铟锡玻璃(ITO)表面制备分支状Cu_2O晶体,Cu_2O与Ag+离子在不同酸(5-磺基水杨酸、柠檬酸、乳酸、樟脑磺酸)诱导下反应生成Ag/Cu_2O复合材料,发现只有在5-磺基水杨酸的作用下可以使Ag纳米粒子均匀地生长在Cu_2O基体上,原因可能是5-磺基水杨酸根与Ag+离子的络合有利于Ag粒子的成核和生长。将Ag/Cu_2O作为SERS基底对亚甲基蓝(MB)、罗丹明B(RhB)和生理浓度范围内的尿素分子进行拉曼检测。结果表明,Ag/Cu_2O纳米颗粒对MB和RhB的检测限可以达到10-9 mol/L,通过尿素浓度和积分强度的关系曲线可实现尿素分子的痕量及定量检测。将分支状Cu_2O晶体与Na_2S反应生成Cu_2O@Cu_7S_4核壳结构,用NH3·H_2O腐蚀Cu_2O核后生成Cu_7S_4壳,Cu_7S_4与Ag+离子发生置换反应后生成玫瑰花状Ag/Ag_2S/Ag_3CuS_2三元纳米复合材料,控制反应时间和掺杂酸(柠檬酸、单宁酸、樟脑磺酸、苯甲酸)种类调节Ag/Ag_2S/Ag_3CuS_2纳米复合材料的形貌,研究Ag/Ag_2S/Ag_3CuS_2纳米复合材料作为SERS基底的分子检测以及作为光催化剂和化学催化的多重性能。结果表明,Ag/Ag_2S/Ag_3CuS_2纳米复合材料的SERS性能较Ag纳米颗粒弱,但优于Cu_7S_4。反应10 min得到的Ag/Ag_2S/Ag_3CuS_2三元纳米复合材料在可见光条件下催化降解甲基橙(MO)性能较理想,研究发现反应过程中超氧阴离子自由基(·O2-)和空穴(h+)是三元纳米复合材料的催化活性物种。在rGO表面生长均匀的Mn_3O_4纳米粒子构筑rGO-Mn_3O_4纳米复合材料,然后rGO-Mn_3O_4与H_2Pt Cl6发生置换反应生成Pt/Mn_3O_4-rGO三元复合材料。通过调节H_2Pt Cl6的用量可以改变Pt纳米粒子的尺寸、分布和含量,比较了不同Pt含量的Pt/Mn_3O_4-rGO三元复合材料的ORR活性。当2~3 nm的Pt纳米粒子均匀分布在rGO-Mn_3O_4载体上时,Pt的负载量为10.06 wt%,较20%的商业Pt/C显示出更好ORR催化活性,表明所制备的Pt/Mn_3O_4-rGO纳米复合材料在低Pt负载量时具有较强的电催化性能。
[Abstract]:The development of nano material preparation technology has made a single component evenly mixed into composite materials as possible, and the synergy between the different components can endow nano composite material. The new controllable morphology and size of noble metal nanoparticles preparation has become a research hotspot in recent years, the application relates to many fields of optical sensing andelectrochemistry. High production costs, introduction of pollutants in the process of reduction reaction, there are problems such as the aggregation of nanoparticles to the popularization and application of nano metal materials Limited. This thesis presents an intermediate valence transition metal oxides (Cu_2O and Mn_3O_4) as sacrificial template preparation method of Pt nano composite Ag the material, with mild experimental conditions, atom economy and other advantages, is conducive to high performance, high purity of noble metal nano material preparation. This study uses intermediate valence transition metal oxides Cu_2O and M N_3O_4 as the noble metal nanoparticles (Ag, Pt) of the reducing agent and the nucleation sites were prepared Ag/Cu_2O nano composite materials, composite materials three yuan three yuan composite material Pt/Mn_3O_4-rGO and Ag/Ag_2S/Ag_3CuS_2, and the application of multielement noble metal nanocomposites by surface enhanced Raman spectroscopy (SERS) molecular detection, visible light photocatalytic the catalytic degradation of methyl orange and oxygen reduction reaction (ORR) and other areas of.Cu_2O and Mn_3O_4 as sacrificial templates with Ag+ or Pt4+ reaction, poor preparation of noble metal nano particle size and morphology controllable composite materials and composite materials with potential between them, especially in the preparation process of replacement reaction in the Ag/Cu_2O and Pt/Mn_3O_4-rGO composite materials the system is not thorough, so nano composite materials can keep the original 3D sacrifice template. The preparation method of the Ag based and Pt based nano composite material Surface cleaning, morphology and uniform novel can detect the performance of noble metal nanoparticles gives better catalysis and molecular. By electrodeposition method on indium tin oxide glass (ITO) surface preparation of branched Cu_2O crystal, Cu_2O and Ag+ ions in different 5- acid (sulfosalicylic acid, citric acid, lactic acid, camphor sulfonic acid) induced reaction of Ag/Cu_2O composite material, found only in the 5- sulfosalicylic acid under the action of the Ag nanoparticles grown on Cu_2O substrate, may be due to complexation of 5- sulfosalicylic acid root and Ag+ ion facilitates the nucleation and growth of Ag particles. The Ag/Cu_2O will be used as SERS substrates for methylene blue (MB), Luo Danming B (RhB) and the physiological concentration range of urea molecules in Raman detection. The results showed that Ag/Cu_2O nanoparticles of MB and RhB of the detection limit can reach 10-9 mol/L, the relation curve of concentration of urea and integral strength Lines can be used to trace and quantitative detection of urea molecules. The branched Cu_2O crystal and Na_2S reaction of Cu_2O@Cu_7S_4 core-shell structure, formation of Cu_7S_4 shell with NH3 H_2O corrosion Cu_2O core, Cu_7S_4 and Ag+ ion replacement reaction generated after rosettelike Ag/Ag_2S/Ag_3CuS_2 three nano composite materials, controlling the reaction time and doping acid (citric acid, tannic acid, camphor sulfonic acid, benzoic acid) were regulating the types of Ag/Ag_2S/Ag_3CuS_2 nanocomposites, Ag/Ag_2S/Ag_3CuS_2 nano composite materials were used as substrates for the detection of molecular SERS as well as the photocatalytic performance of multi agent and chemical catalysis. The results show that the performance of SERS Ag/Ag_2S/Ag_3CuS_2 nanocomposites with Ag nanoparticles is weak, but the reaction is better than that of Cu_7S_4. 10 min Ag/Ag_2S/Ag_3CuS_2 three nanocomposites under visible light catalytic degradation of methyl orange (MO) ideal performance The study found that the reaction process of superoxide anion radical (O2-) and hole (h+) is the catalytic active species and three yuan of nano composites. The growth of Mn_3O_4 nanoparticles with uniform structure of rGO-Mn_3O_4 nano composite materials on the surface of rGO, rGO-Mn_3O_4 and H_2Pt and Cl6 put three yuan composite reaction by adjusting the H_2Pt Cl6 Pt/Mn_3O_4-rGO. The amount of Pt can change the particle size, distribution and content, compared with three yuan of composite materials with different content of Pt Pt/Mn_3O_4-rGO ORR Pt 2~3 nm activity. When the nanoparticles are evenly distributed on the rGO-Mn_3O_4 carrier, Pt loading is 10.06 wt%, compared with 20% commercial Pt/C showed better catalytic activity of ORR, which indicated that Pt/Mn_3O_4-rGO nanocomposites have strong electrocatalytic properties with low Pt loading.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1;O643.36

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