具有表面拉曼增强活性的新型银纳米材料的合成和表征

利用简易无模板湿化学法合成了由纳米片组装的具有三维分级结构的银纳米材料。场发射扫描电子显微镜表明柠檬酸氢二铵在这种结构形成过程中起到很重要的作用。X射线衍射和透射电子显微镜表征进一步证明了这种结构的形成。此外本文还对这种分级结构进行了紫外和拉曼表征。这种新型的银纳米结构有望作为一种高灵敏度的表面拉曼增强基底。     

含5-氟尿嘧啶的复合结构纳米颗粒的合成及其光谱研究

合成了包覆有5-氟尿嘧啶的银/二氧化硅复合结构纳米颗粒.用透射电子显微镜、红外光谱和拉曼光谱对合成的化合物进行了表征.讨论了药物分子在银表面的拉曼增强效应以及二氧化硅壳层对它的影响.     

利用去湿现象制备具有SERS活性的银纳米粒子图案

构建了具有表面增强拉曼散射(SERS)活性的二维有序环状与盘状的银纳米粒子结构, 利用CTAB包覆银纳米粒子的氯仿溶液直接在图案化的金基底上进行去湿, 当改变银纳米粒子的浓度时可以得到不同的图案. 利用原子力显微镜(AFM)对其结构进行了表征, 以4-巯基吡啶作为探针分子, 采用表面增强拉曼成像技术研究了这种基底的SERS活性, 这将为SERS的研究开拓新的领域.     

内部具有可移动金核的中空银纳米颗粒的制备、表征及其表面增强拉曼效应

采用振荡法和种子生长技术制备出核壳结构的Au@SiO2纳米颗粒及夹层结构的Au@SiO2@Ag纳米颗粒, 用HF将Au@SiO2@Ag NPs夹层的SiO2溶解, 得到内部带有粒径为30 nm的可移动金核、壳层厚度约为30 nm的中空银纳米颗粒(Au@air@Ag NPs). 用扫描电子显微镜和透射电子显微镜对所得到的纳米微球的形貌进行了表征, 并以罗丹明B为探针分子研究了Au@air@Ag 纳米颗粒的表面增强拉曼(SERS)效应, 发现Au@air@Ag 纳米颗粒是一种可应用于SERS的理想材料.     

电子显微镜技术表征聚乙二醇包覆的银纳米线的显微结构特征

以缓慢的水热合成法制备聚乙二醇(PEG)包覆的银纳米线,并用电子显微镜对其微观形貌和结构进行了表征。PEG是一种对银表面呈弱亲和性的水溶性聚合物,它在银纳米线合成中既作为Ag+的还原剂,又作为银线的包覆剂。扫描电镜和透射电镜表征显示,这种银纳米线的直径为80～300 nm,长度大于100μm;并且其中一部分银纳米线首尾相接形成了闭合纳米线圈,是首例以化学法制取的金属闭合纳米线圈。闭合环状纳米线的形成进一步支持了金属纳米线的融合生长机制。透射电镜和选区电子衍射以及银纳米线横截面切片的透射电镜表征显示,这种PEG包覆的银纳米线具有轴对称的五重挛晶结构。银纳米线经过长时间的水热孵化而保持其五重挛晶结构,这一点与某些文献报道的情况有所不同,说明银纳米线结构及其演化具有一定的复杂性。     

花状银微纳米结构的合成及SERS性质

通过简便的水溶液方法制备出一种新颖的由纳米片组成的花状银微纳米结构, 采用XRD, SEM, TEM, HRTEM和SAED等手段进行了表征. 考察了反应体系pH值对产物形貌的影响, 并对花状银微纳米结构的形成机理进行了初步探讨. 所制得的微纳米结构由许多纵横交错的纳米片组成. 实验结果表明, 制备的银微纳米结构作为表面增强拉曼散射(Surface-enhanced Raman Scattering, SERS)的基底具有很强的活性.     

表面增强拉曼光谱检测联苯胺

采用柠檬酸钠还原法制备了具有表面增强拉曼散射(SERS)活性的银纳米溶胶, 利用透射电子显微镜、 扫描电子显微镜和紫外-可见光谱仪对银纳米溶胶进行了表征. 对水相的联苯胺进行了SERS研究, 并对联苯胺的拉曼谱带进行了归属. 考察了团聚剂氯化镁的浓度对检测的影响, 发现随着氯化镁浓度的变大, SERS信号呈现出先增大后减弱的趋势, 即氯化镁的浓度存在一个最佳值, 此时联苯胺的检测限可达到10^-8 mol/L.     

Ag/ZnO纳米纤维的制备及光催化性能

采用静电纺丝技术及煅烧法制备了氧化锌纳米纤维, 然后采用水热法将银纳米颗粒负载到了氧化锌纳米纤维表面. 利用X射线衍射(XRD)、 X射线光电子能谱(XPS)、 能量色散X射线光谱(EDX)、 扫描电子显微镜(SEM)及透射电子显微镜(TEM)等技术对合成的Ag/ZnO纳米纤维的结构和组成进行了表征. SEM结果表明, 直径在5~100 nm之间的银纳米颗粒附着在直径在80~330 nm之间的氧化锌纤维表面形成了异质结构. 以常见的有机污染物甲基橙、 亚甲基蓝和罗丹明B等为降解底物, 对Ag/ZnO纳米纤维的光催化性能进行了表征. 结果表明, 负载银纳米颗粒后, 复合催化剂的光催化性能明显提高.     

Cu2O/Ag纳米复合物的表面增强拉曼光谱

用一种简单的化学还原方法制备了银纳米粒子包覆的氧化亚铜（Cu2O）纳米复合物。扫描电子显微镜显示Cu2O 为八面体型的纳米粒子,表面光滑,结构对称。包覆的Ag部分占据Cu2O粒子表面。通过比较Ag/Cu2O纳米复合物、Ag溶胶及Cu纳米粒子表面吸附的4-巯基吡啶（4-Mpy）分子表面增强拉曼光谱（SERS）发现,利用此方法得到了Cu2O粒子表面吸附分子的拉曼光谱。银纳米粒子所产生的电磁场增强又增强了吸附在Cu2O上的4-Mpy拉曼信号。这种方法为初步研究Cu2O表面吸附分子性质提供了依据,扩宽了SERS的使用范围,使SERS应用在纳米半导体材料上成为可能。     

Ag/ZnO纳米纤维的制备及光催化性能（英文）

采用静电纺丝技术及煅烧法制备了氧化锌纳米纤维,然后采用水热法将银纳米颗粒负载到了氧化锌纳米纤维表面.利用X射线衍射(XRD)、X射线光电子能谱(XPS)、能量色散X射线光谱(EDX)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)等技术对合成的Ag/ZnO纳米纤维的结构和组成进行了表征.SEM结果表明,直径在5~100 nm之间的银纳米颗粒附着在直径在80~330 nm之间的氧化锌纤维表面形成了异质结构.以常见的有机污染物甲基橙、亚甲基蓝和罗丹明B等为降解底物,对Ag/ZnO纳米纤维的光催化性能进行了表征.结果表明,负载银纳米颗粒后,复合催化剂的光催化性能明显提高.     

Silver nanoparticles active as surface-enhanced Raman scattering substrates prepared by high energy irradiation

In surface-enhanced Raman scattering (SERS) technique the preparation of metal substrates containing minimum hindrance from impurities is an important issue. The synthesis of silver nanoparticles (Ag NPs) active as SERS substrates and having the above-mentioned advantage, were obtained by electron beam irradiation of Ag⁺ aqueous solutions. Ag⁺ ions were reduced by free radicals radiolytically generated in solution without the addition of chemical reductants or stabilizing agents.The metal colloids were characterised by UV-Vis spectroscopy and scanning electron microscopy, monitoring the nanoparticles’ growth process that depends on the irradiation dose and the initial AgNO₃ concentration. Nanoparticles of long-time stability and with different size and shape, included silver nanocubes, were synthesised by varying the irradiation dose. Different tests on the SERS activity of Ag NPs obtained by electron beam irradiation were performed by using benzenethiol as a probing molecule, achieving a good magnification of the adsorbate Raman bands.     

Raman investigations of SERS activity of Ag nanoclusters on a TiO2-nanotubes/Ti substrate

Tubular arrays of TiO₂ nanotubes (ranging in diameter from 40 to 110 nm) on a Ti substrate were used as a support for Ag deposits obtained by the sputter deposition technique where the amount of Ag varied from 0.01 to 0.2 mg Ag/cm². Those composite supports were intended for surface-enhanced Raman scattering (SERS) investigations. Composite samples of Ag/TiO₂ nanotube/Ti were studied with the aid of scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) to reveal their characteristic morphological and chemical features. Raman spectra of pyridine (as a probe molecule) were measured at different cathodic potentials ranging from −0.2 down to −1.2 V after the pyridine had been adsorbed on the Ag-covered TiO₂ nanotube/Ti substrates. In addition, SERS spectra on a bulk standard activated Ag substrate were also measured.The SERS activity of the composite samples was strongly dependent on the amount of Ag deposit. At and above 0.06 mg Ag/cm², the SERS signal was even higher than that for the Ag reference substrate. The high activity of the composites is mainly a result of their specific morphology. The high SERS sensitivity on the surface morphology made it possible to monitor very small temporal changes in the Ag clusters. This rearrangement was not detectable with microscopic (SEM) or microanalytical (AES) methods.     

Cu掺杂TiO_2作为SERS基底的研究

本文采用溶胶-水热法制备了TiO2及Cu掺杂的TiO2纳米粒子作为表面增强拉曼光谱(SERS)活性基底,观察到当4-巯基苯甲酸吸附在3%Cu掺杂的TiO2表面上时,其SERS信号得到了最大程度的增强.Cu离子掺杂进TiO2晶格时会使TiO2表面的缺陷浓度(表面态)得到增加,一定量的缺陷浓度对TiO2-to-Molecule的电荷转移机理起到促进作用,进一步证明了化学增强机理在SERS现象的贡献.     

Controllable growth of silver nanostructures by a simple replacement reaction and their SERS studies

Hierarchical silver nanostructures, consisting of dendritic (symmetric branched) and fractal patterns (randomly ramified), were synthesized very easily by dropping a droplet of AgNO₃-HF solution on silicon wafers. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and open circuit potential-time (Ocp-t) measurement demonstrated that the two nanostructures converted with the reaction composition. The structural evolution was tentatively explained with the theory that oriented growth was determined by the anisotropy of the solid–liquid interfacial energy and the oriented attachment-based aggregation mechanism. Results on surface-enhanced Raman scattering (SERS) signals of the silver films with hierarchical nanostructures demonstrate that SERS is sensitive to silver nanostructures.     

帽状铜纳米粒子的制备及表面增强拉曼散射活性研究

采用真空热蒸发法在SiO₂纳米粒子自组装单层膜上沉积铜薄膜制备了帽状铜纳米粒子。用扫描电镜、原子力显微镜和紫外-可见-近红外分光光度计对帽状复合纳米粒子的表面形貌和光学性质进行了表征。以亚甲基蓝和吡啶-(2-偶氮-4)间苯二酚为探针分子,研究了该复合纳米粒子的表面增强拉曼散射(SERS)活性。通过比较吸附在不同基底上的吡啶-(2-偶氮-4)间苯二酚的谱峰强度,探讨了SERS效应与表面等离子体共振(SPR)的关系。     

Detection of polycyclic aromatic hydrocarbon (PAH) compounds in artificial sea-water using surface-enhanced Raman scattering (SERS)

This paper reports an accurate synthesis of surface-enhanced Raman scattering (SERS) active substrates, based on gold colloidal monolayer, suitable for in situ environmental analysis. Quartz substrates were functionalized by silanization with (3-mercaptopropyl)trimethoxysilane (MPMS) or (3-aminopropyl)trimethoxysilane (APTMS) and they subsequently reacted with colloidal suspension of gold metal nanoparticles: respectively, the functional groups SH and NH₂ bound gold nanoparticles. Gold nanoparticles were prepared by the chemical reduction of HAuCl₄ using sodium tricitrate and immobilized onto silanized quartz substrates. Active substrate surface morphology was characterized with scanning electron microscopy (SEM) measurements and gold nanoparticles presented a diameter in the range 40-100 nm. Colloidal hydrophobic films, allowing nonpolar molecule pre-concentration, were obtained. The surfaces exhibit strong enhancement of Raman scattering from molecules adsorbed on the films. Spectra were recorded for two PAHs, naphthalene and pyrene, in artificial sea-water (ASW) with limits of detection (LODs) of 10 ppb for both on MPMS silanized substrates.     

Thermal and plasma synthesis of metal oxide nanoparticles from MOFs with SERS characterization

Aluminum oxide (Al₂O₃) and chromium oxide (Cr₂O₃) nanoparticles were synthesized by thermolysis of metal-organic frameworks (MOFs). Further O₂ plasma treatment is required to obtain high crystalline quality metal oxides. The composition and morphology of metal oxide nanoparticles were confirmed by powder X-ray diffraction and scanning electron microscopy characterization, respectively. The quality of synthesized metal oxides was also examined by observing the surface-enhanced Raman scattering (SERS) spectra of methyl orange adsorbed on Al₂O₃ and Cr₂O₃. The observed SERS effect can be ascribed to charge-transfer (CT) resonance effect between methyl orange and metal oxide surfaces. UV–vis absorption spectra and DFT calculations of metal oxide- methyl orange complexes have confirmed that the observed SRS effect is due to CT resonance between the metal oxide nanoparticles and the adsorbed methyl orange molecules.     

Cancer cell detection and imaging: MRI-SERS bimodal splat-shaped Fe3O4/Au nanocomposites

In this paper, a kind of splat-shaped Fe₃O₄/Au nanocomposites was synthesized. The magnetic resonance imaging/surface-enhanced Raman scattering (MRI/SERS) studies demonstrated that as-synthesized Fe₃O₄/Au nanocomposites may be a promising MRI/SERS dual probe for the tumor detection.     

SERS approach for Zn(II) detection in contaminated soil

Soil contamination by metals is a common problem encountered in many industrialized countries. In this work we present a new approach for heavy metals detection by using surface-enhanced Raman scattering (SERS) spectroscopy. Zn(II) can be clearly determined by SERS in contaminated soil by using 4-(2-pyridylazo) resorcinol (PAR) as chelating molecule for the metal ion. The SERS spectra of PAR, of its metal chelates and of the soil extract-PAR mixture were recorded using a hydroxylamine reduced silver colloid. An excellent match of the PAR-contaminated soil extracts SERS spectrum to the Zn(PAR)₂ SERS spectrum can be observed, demonstrating the presence of Zn(II) in the soil probes. Density functional theory (DFT) based calculations were also performed for a reliable assignment of SERS spectra.