Ag@SiO2纳米颗粒的制备及其在H2O2检测上的应用

利用柠檬酸三钠还原硝酸银制备了银纳米颗粒(AgNPs), 然后通过氨水水解正硅酸乙酯(TEOS)的方法, 在AgNPs上沉积SiO₂, 制备出以Ag为核, SiO₂为壳的复合纳米颗粒(Ag@SiO₂). 调节TEOS用量, 可以控制SiO₂层的厚度. 根据AgNPs的局域表面等离激元共振(LSPR)效应, 将制得的Ag@SiO₂颗粒用于H₂O₂的检测, 检测下限为1 μmol/L, 并可以通过控制SiO₂层的厚度方便地调节Ag@SiO₂颗粒与H₂O₂反应的速率. 与传统方法相比, 具有简单、快速、成本低的优点. 分别运用TEM、紫外-可见分光光度计对反应前后Ag@SiO₂颗粒形貌及反应过程中其LSPR吸收的变化进行了表征.     

表面等离激元金属纳米粒子的多元化结构及应用

目前, 单一的金属纳米粒子结构已经难以满足多学科交叉发展的需求. 因此, 将多种金属纳米粒子(如不同尺寸、 形状、 组分等)集成在同一基底表面, 能够充分发挥不同金属纳米粒子的性质和优势, 极具研究价值和应用价值. 本文介绍了多元化表面等离激元纳米粒子结构的构筑方法, 以及其在信息编码、 光电器件、 能源催化等领域的应用. 最后, 提出了当前在多元化结构制备中存在的挑战, 并展望了利用多元化结构实现性能提升的前景.     

金纳米壳材料的可控制备及其SERS应用

采用种子介导生长法,以H₂O₂为还原剂介导金纳米壳的生长,并研究该生长过程中金纳米壳的表面结构与其SERS活性的关系。结果表明,随着还原剂H₂O₂浓度的增大,二氧化硅表面金纳米粒子不断长大,最终形成完整的金壳层,并伴随着SERS活性的不断增强,且控制材料的表面粗糙程度,可更大的增强其SERS活性。以此金纳米壳作为SERS基底可实现有机污染物的实时原位在线检测。     

静电纺丝法制备CuNi纳米粒子/碳纳米纤维电分析检测H2O2

通过静电纺丝技术制备了铜镍纳米粒子掺杂的碳纳米纤维(CuNi-CNFs),并用于过氧化氢(H_2O_2)的电分析检测。CuNi-CNFs纳米复合材料的组分、结构通过X射线衍射、拉曼光谱等方法进行了表征。该纳米复合材料中,CNFs具有较大的比表面积和良好的导电性,而CuNi纳米粒子具有良好的电催化活性。由于Cu,Ni和CNFs的协同作用,CuNi-CNFs纳米复合材料对H_2O_2表现出良好的电催化作用,传感器的线性范围为0. 01～6 mmol/L。     

金纳米壳球体的制备及其潜在的生物学应用

利用分子自组装和胶体还原化学制备出具有核-壳结构的金纳米壳球体Au@SiO₂; 通过透射电子显微镜(TEM)、X射线光电子能谱 (XPS)和紫外-可见分光光度计对Au@SiO₂的制备过程及其在全血中的光学特性进行了研究. 结果表明, 通过改变复合颗粒Au-APTES-SiO₂的浓度, 可以得到具有合理核-壳比例的Au@SiO₂, 其等离激元共振峰位于光谱的近红外区, 这使得具有红外消光特性的金纳米壳球体具有潜在的生物学应用价值.     

Ag@SiO2纳米复合物金属增强荧光释放法检测葡萄糖

制备了Ag@SiO2纳米复合物,罗丹明B通过物理掺杂结合在SiO2壳层。由于金属增强荧光效应,罗 丹明B的荧光增强到4.7倍。Ag核易被H2O2氧化,Ag核氧化后产生荧光增强释放效应。基于金属增强荧光 释放建立了一种新型葡萄糖检测方法,采用交联法在罗丹明B掺杂的Ag@SO2纳米复合物的SiO2壳层固定 葡萄糖氧化酶。检测浓度范围为0.2～6.8 mmol/L,检测限可达0.06 mmol/L。由于H2O2氧化Ag核反应迅 速,检测体系对葡萄糖的响应快速。     

大面积多元化表面等离激元金纳米粒子结构的制备

具有显著表面等离激元共振效应的贵金属纳米粒子因其独特的光电学性质在许多领域表现出了潜在的应用价值。结合纳米压印技术与自组装技术发展了一种高效的多元化纳米粒子结构的制备方法,并制备了一种由不同尺寸金纳米粒子构成的周期性表面等离激元纳米粒子结构。实验结果证明此种方法在大批量制备和结构多元化的控制方面具有独特的优势。利用不同的表面等离激元纳米粒子结构对不同荧光分子增强效果的差异,设计了2种具有明显明暗差异的荧光条码,展示了多重的荧光增强响应。     

Ti3C2Tx/Au@Pt纳米花复合膜的制备及其无酶H2O2传感器的应用

基于二维过渡金属碳化物(MXene)-Ti_3C_2T_x材料的导电性与Au@Pt纳米花的催化活性,组装了一种用于超灵敏和快速检测H_2O_2含量的Ti_3C_2T_x/Au@Pt纳米花无酶传感器。通过发射扫描电镜和X-射线衍射对制备的Ti_3C_2T_x进行表征。结果表明Ti_3C_2T_x材料表现出特有的手风琴结构,Ti_3C_2T_x/Au@Pt为以Au粒子为中心,Pt粒子环绕周围组成蒲公英状纳米球。研究了H_2O_2在Ti_3C_2T_x/Au@Pt纳米花修饰玻碳电极上的循环伏安曲线和时间电流曲线,结果显示该修饰电极检测H_2O_2具有线性范围良好(0.03～1 100μmol/L)、灵敏度高(检出限可达0.02μmol/L)、抗干扰性和再现性好等优点。与传统滴定法相比,该新型无酶传感器能在复杂环境下快速准确检出H_2O_2含量。     

纳米金标记抗体增强SPR检测大肠杆菌O157∶H7

将金纳米粒子(AuNPs)标记的大肠杆菌O157∶H7(E.coli O157∶H7)的多克隆抗体(PAb)作为二抗,采用氨基偶联法将PAb固定在传感器表面作为一抗,通过三明治方法用双通道表面等离子体子共振(SPR)传感器对E.coli O157∶H7进行检测,并与SPR直接法检测进行了比较.结果表明,直接法的检出限为103cfu/mL,线性范围为103～109cfu/mL;AuNPs增强三明治法的检出限为10 cfu/mL,线性范围为10～1010cfu/mL,灵敏度比直接法提高了100倍,且具有更宽的检测范围.本方法不仅检测时间短,而且具有良好的选择性和重现性.     

金纳米棒的表面改性及与H_2O_2的作用

通过调控过氧化氢与金纳米棒相互作用时溶液的H~+和Br~-浓度,考察了过氧化氢刻蚀金纳米棒的条件.通过静电相互作用将聚苯乙烯磺酸钠修饰到带正电的金纳米棒表面,并探讨了表面配体变化对过氧化氢与金纳米棒相互作用的影响,比较了聚苯乙烯磺酸钠浓度改变对过氧化氢刻蚀金纳米棒所引起的等离子体吸收峰的变化.结果表明,过氧化氢与金纳米棒作用过程中,H~+浓度增加可以加快刻蚀反应速率,Br~-起到稳定金离子的作用.采用聚苯乙烯磺酸钠修饰抑制了过氧化氢对金纳米棒的刻蚀,当聚苯乙烯磺酸钠与金纳米棒表面的CTAB完全作用后,复合材料电位接近零,金纳米棒的稳定性降低,继续增加聚苯乙烯磺酸钠的量至电位为负,复合材料稳定性增加.     

Simultaneous Sensing of H2O,D2O and HOD through Peroxo Vibrations

Detection of HOD simultaneously in the presence of a mixture of H₂O and D₂O is still an experimental challenge. Till date, there is no literature report of simultaneous detection of H₂O, D₂O and HOD based on vibrational spectra. Herein we report simultaneous quantitative detection of H₂O, D₂O and HOD in the same reaction mixture with the help of bridged polynuclear peroxo complex in absence and presence of Au nanoparticles on the basis of a peroxide vibrational mode in resonance Raman and surface enhanced resonance Raman spectrum. We synthesize bridged polynuclear peroxo complex in different solvent mixture of H₂O and D₂O. Due to the formation of different nature of hydrogen bonding between peroxide and solvent molecules (H₂O, D₂O and HOD), vibrational frequency of peroxo bond is significantly affected. Mixtures of different H₂O and D₂O concentrations produce different HOD concentrations and that lead to different intensities of peaks positioned at 897, 823 and 867 cm⁻¹ indicating H₂O, D₂O and HOD, respectively. The lowest detection limits (LODs) were 0.028 mole fraction of D₂O in H₂O and 0.046 mole faction of H₂O in D₂O. In addition, for the first time the results revealed that the cis-peroxide forms two hydrogen bonds with solvent molecules.     

Palladium Nanoparticles Embedded into Graphene Nanosheets: Preparation,Characterization, and Nonenzymatic Electrochemical Detection of H2O2

A novel nonenzymatic H₂O₂ sensor based on a palladium nanoparticles/graphene (Pd‐NPs/GN) hybrid nanostructures composite film modified glassy carbon electrode (GCE) was reported. The composites of graphene (GN) decorated with Pd nanoparticles have been prepared by simultaneously reducing graphite oxide (GO) and K₂PdCl₄ in one pot. The Pd‐NPs were intended to enlarge the interplanar spacing of graphene nanosheets and were well dispersed on the surface or completely embedded into few‐layer GN, which maintain their high surface area and prevent GN from aggregating. XPS analysis indicated that the surface Pd atoms are negatively charged, favoring the reduction process of H₂O₂. Moreover, the Pd‐NPs/GN/GCE could remarkably decrease the overpotential and enhance the electron‐transfer rate due to the good contact between Pd‐NPs and GN sheets, and Pd‐NPs have high catalytical effect for H₂O₂ reduction. Amperometric measurements allow observation of the electrochemical reduction of H₂O₂ at 0.5 V (vs. Ag/AgCl). The H₂O₂ reduction current is linear to its concentration in the range from 1×10^?9 to 2×10^?3 M, and the detection limit was found to be 2×10^?10 M (S/N=3). The as‐prepared nonenzymatic H₂O₂ sensor exhibits excellent repeatability, selectivity and long‐term stability.     

Surface‐Enhanced Fluorescence from Fluorophore‐Assembled Monolayers by Using Ag@SiO2 Nanoparticles

A new and simple procedure to enhance the fluorescence of analytes on the surfaces of a solid substrate is demonstrated based on Ag@SiO₂ nanoparticles. Two kinds of silver–silica core–shell nanoparticles with shell thicknesses of around 3 and 15 nm have been prepared and used as enhancing agents, respectively. By simply pipetting drops of the enhancing agents onto substrate surfaces with Rose Bengal monolayers, an enhancement of about 27 times, compared with the control sample, is achieved by using the Ag@SiO₂ nanoparticles with shells of about 3 nm, whereas an enhancement of around 11.7 times is obtained when using those with thicker shells. The effects of shell thickness and surface density of the enhancing agents on the enhancement have been investigated experimentally. The results show that this method can be potentially helpful in fluorescence‐based surface analysis.     

纳米α-Fe2O3/(IPDI-HTPB)复合粒子的制备及其催化性能研究

为改善纳米α-Fe₂O₃在复合推进剂中的分散性，提高其催化性能，选择推进剂的配方组分固化剂异氟尔酮二异氰酸酯（IPDI）为嫁接桥梁，将端羟基聚丁二烯（HTPB）接枝在纳米α-Fe₂O₃粒子的表面，制得纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子.首先研究了IPDI与HTPB反应动力学，优化制备条件；然后采用X射线衍射仪（XRD）、透射电子显微镜（TEM）、傅里叶变换红外光谱仪（FTIR）和热重分析（TGA）等手段对复合粒子的结构进行表征，采用DTA对比了复合前后纳米α-Fe₂O₃粒子对高氯酸铵（AP）热分解的催化性能的影响.结果表明，依靠IPDI的偶联作用，可将HTPB接枝在纳米α-Fe₂O₃的表面，包覆层厚度约为5 nm，改性后的纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子的分散性大幅提高，纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子对AP的热分解的催化性能也明显优于纯纳米α-Fe₂O₃粒子.     

金纳米粒子修饰的三维花状二硫化钼复合材料的制备及其用于检测过氧化氢的研究

以Na_2MoO_4·2H_2O为钼源,硫脲为硫源和还原剂,氧化多壁碳纳米管(o-MWNTs)和氧化石墨烯(GO)为原料,采用水热法合成了三维花状MoS_2/GO/o-MWNTs纳米复合材料,并进一步采用原位还原法将金纳米粒子修饰至MoS_2/GO/o-MWNTs纳米复合材料表面。通过场发射扫描电镜、透射电镜、XRD、XPS等对上述复合材料进行表征。结果表明,该复合纳米材料具有3D花状球结构,且Au纳米粒子已成功生长在其花瓣状片层上。采用滴涂法制得该复合材料修饰的玻碳电极,研究了过氧化氢在该电极上的电化学行为。结果表明:该电极对过氧化氢的电还原表现出强催化活性。通过对不同浓度过氧化氢的催化还原,得出该电极对过氧化氢的线性范围为12.0×10~(-9)～31.0×10~(-6) mol/L,灵敏度为56.6μA/(mmol·L~(-1)),检出限为12.0×10~(-9) mol/L。     

谷胱甘肽修饰金纳米棒的制备及与Cu~(2+)的作用

制备了谷胱甘肽(GSH)功能化的金纳米棒复合材料,根据金纳米棒的等离子体吸收峰对其组装排列敏感的特性,研究了功能化的金纳米棒在不同p H值下的组装行为及与Cu2+离子作用后引起的聚集程度、排列方式和光学吸收等变化.同时,测试了纯金纳米棒和谷胱甘肽修饰的金纳米棒分别与铜离子作用后所得复合材料的光热转换性能.结果表明,相对于纯金纳米棒材料强的光热转换效应,铜离子能明显降低复合材料的光热转换效应,与其它金属离子比较,GSH修饰的金纳米棒的等离子光学特性对铜离子具有选择性的变化.     

纳米钯修饰电极在碱性条件下对过氧化氢的测定

采用单电位阶跃计时电流法制备了Pd纳米粒子修饰复合陶瓷碳电极(Pd/CCE)。研究了该修饰电极对H2O2的电催化氧化性能。结果表明,Pd/CCE修饰电极在碱性介质中对H2O2的氧化具有强电催化活性。在0.1 mol.L-1NaOH溶液中采用动态安培法检测H2O2,线性范围为2.0×10-6~2.6×10-3mol.L-1,r=0.999 3,检出限(3sb)为5.0×10-7mol.L-1,灵敏度为143.8μA.(mmol.L-1)-1。该法用于过氧化氢消毒液中H2O2的测定,结果满意。     

Microwave-assisted One-pot Synthesis of Ag NPs/C and Its Application in H2O2 and Glucose Detection

The facile preparation of Ag NPs/C via a one-pot strategy was carried out by microwave treatment of a mixed aqueous solution of AgNO₃ and glucose at 180℃ for 20 min without the presence of extra reducing agent. The as-synthesized Ag NPs/C showed high catalytic performance toward the reduction of H₂O₂. The H₂O₂ sensor constructed with as-synthesized Ag NPs/C exhibited a short amperometric response time of less than 2 s. The linear range was approximately (0.1-50) mmol/L(r=0.997), and the detection limit was approximately 3.3 μmol/L at a signal-to-noise ratio of 3. A glucose biosensor was fabricated by immobilizing glucose oxidase onto Ag NPs/C- modified glassy carbon electrode to detect glucose. The glucose sensor had a wide linear response range of 2-22 mmol/L(r=0.999) and a detection limit of 190 μmol/L.