JOURNAL OF APPLIED PHYSICS
·
2019
·Vol. 125
·期 18
·
IF 2.328
Zhang Kaixuan,Xu Na,Jia Mengyu,Li Ruoping,Huang Mingju
Noble-metal-based surface-enhanced Raman spectroscopy (SERS) substrates can be employed as catalysts capable of generating hot electrons to drive chemical reactions of target molecules adsorbed on their surface. However, the localized surface plasmons excited from pure noble metals generally exhibit relatively low hot-electron utilization efficiency with the reactants owing to charge carrier recombination. This problem can be solved by integrating heterogeneous structures with the noble metal. Herein, we describe the fabrication of bifunctional SERS substrates by constructing Au@Ag, Au@Ag 2 S, and Au@SiO 2 core-shell nanoparticles and evaluate the effects of the three heterostructures (Au cores encapsulated by shells composed of metal, semiconductor, or insulator) on the hot-electron transfer efficiency by in situ monitoring of the catalytic dimerization of p -nitrophenol to form p , p ′-dimercaptoazobenzene under 632.8 nm laser illumination. The developed SERS strategy opens up new opportunities for exploring hot-electron-induced reactions as well as providing a useful reference for photocatalyst selection.
研究领域:
材料科学
·
光催化
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2015
·
IF 2.752
Zhihai Cao,Hangnan Chen,Shudi Zhu,Zhijie Chen,Chang Xu,Dongming Qi,Ulrich Ziener
A convenient method based on the inverse miniemulsion technique was proposed to prepare raspberry-like Au/SiO 2 nanocomposite particles (NCPs). HAuCl 4 was incorporated into porous SiO 2 nano-supports through a sol–gel process of a silica precursor in inverse miniemulsions. Raspberry-like Au/SiO 2 NCPs were subsequently obtained through in situ reduction of the incorporated HAuCl 4 by hydrazine at the surface of SiO 2 nano-supports. Most of Au nanoparticles (NPs) were half-embedded in the SiO 2 nano-supports and were covered by a thin layer of porous SiO 2 , offering a good morphological stability to the Au/SiO 2 NCPs. The content of Au NPs of the Au/SiO 2 NCPs could be adjusted by the loading of HAuCl 4 . The influences of the HAuCl 4 loading on the particle size and particle morphology of the Au/SiO 2 NCPs, the pore properties of the SiO 2 nano-supports, as well as the properties of the Au NPs were systematically investigated. The formation mechanism of the raspberry-like Au/SiO 2 NCPs was discussed. All the synthesized Au/SiO 2 NCPs displayed a high catalytic activity towards the reduction of p -nitrophenol.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RAMAN SPECTROSCOPY
·
2013
·Vol. 44
·期 8
·1120-1125
·
IF 2.679
Bi-Qi Zhang,Song-Bo Li,Qing Xiao,Ju Li,Jian-Jun Sun
The recently reported shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) is considered as the next generation of advanced spectroscopy for its surface and molecular generality. With the aim to utilize the virtues of shell-isolated strategy and advance the SHINERS technique, we introduce a silane-based rapid synthesis method of silica-coating Au nanorods (Au@SiO 2 NRs) with manoeuvrable ultra-thin shell and tunable SPR. The results demonstrate that the SPR of Au NRs could be optimized to obtain large Raman enhancement using either 633 nm or 785 nm laser. Differing from previously reported Au@SiO 2 NRs synthesis method, we can tune the silica shell thickness within several nanometers to maximize the Raman signal while effectively eliminating the exterior interference. And this advanced synthesis method has also significantly reduced the silica-coating time from one day to ca. 1 h. This method as a new development of SHINERS technique has successfully got enhanced signal in solution Raman tests of malachite green, giving a great potential to be extended to in-situ measurement for daily life detection. Copyright © 2013 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
光谱学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2022
·
IF 5.304
Xueyuan Li,Xuezhong Du
Surface enhanced electrochemiluminescence (SEECL) emission of the Ru(bpy) 3 2+ (bpy = 2,2′-bipyridyl)/tripropylamine (TPA) system by [email protected] 2 core/shell nanoparticles (NPs) was achieved owing to the electromagnetic field enhancement induced by localized surface plasmon resonance (LSPR) of internal Au cores. The Ru(bpy) 3 2+ /TPA system in electrolyte solution showed a maximum ECL enhancement when a glassy carbon electrode (GCE) was modified with [email protected] 2 NPs ( [email protected] 2 /GCE; Au core, ca. 68 nm; silica shell, 12 nm). The ECL emission of the system in the case of [email protected] 2 /GCE was 29 fold stronger than the ECL emission in the case of bare GCE, ca. 39 fold stronger than the ECL emission in the case of hollow silica NP-modified GCE, and 100 fold stronger than the ECL emission in the case of AuNP-modified GCE. To the best of our knowledge, the respective folds of ECL enhancement in the Ru(bpy) 3 2+ /TPA system by the LSPR-induced electromagnetic field of AuNPs are the largest reported to date. The ECL emission of TPA •+ radical cations was detected for the first time taking the advantage of the electromagnetic field enhancement. A SEECL platform based on the [email protected] 2 /GCE in the Ru(bpy) 3 2+ /TPA system was constructed for the detection of dopamine (DA). This is the first example that the AuNP-enhanced ECL emission was quenched by DA for the selective detection of DA, and a wide linear range of 0.01–600 μM directly relevant to DA concentration was obtained with a low detection limit of 0.004 μM and high sensitivity and accuracy. The mechanism that the ECL emission of the Ru(bpy) 3 2+ /TPA system was quenched by DA for the detection of DA was clearly elaborated. The level of DA in human serum was determined using the SEECL platform.
研究领域:
分析化学
·
电化学
·
纳米技术
·
生物传感器
✓ 已验证
产品关联
DOI
高影响因子
Analytical Methods
·
2023
·Vol. 15
·期 35
·4494-4505
·
IF 3.1
Chao Sun,Lizheng Wang,Naiyu Guo,Runze Hu,Li Ye,Zhiming Hu,Jianjun Ding
Surface-enhanced Raman scattering (SERS) has a unique fingerprint spectrum, which allows for rapid, highly sensitive, and non-destructive detection without the need for sample pretreatment. However, SERS substrates have disadvantages such as short storage time and poor reproducibility. In this study, carbon nanotubes, gold, and silver were combined to take advantage of their inherent structural and characteristic properties that enhance the Raman effect. A new type of SERS composite substrate, CNTs/Ag@Au/SiO2, was prepared using a hydrothermal method and seed growth method. The substrate was characterized using transmission electron microscopy (TEM), and the average distance between the core–shell nanoparticles was found to be 3.1 nm, which is more suitable than other gold–silver combined core–shell structures and significantly improves the SERS enhancement factor. The substrate demonstrated high sensitivity even at low concentrations of probe molecules and good uniformity at five randomly selected locations. After storage for 45 days, the substrate still exhibited good stability. In most gold–silver combined core–shell structures, the detection limit for Rhodamine 6G (R6G) is 10−9 mol L−1, while in this substrate, the detection limit for R6G is 10−11 mol L−1. Furthermore, the contribution of the substrate's enhancement was deeply investigated using finite-difference time-domain (FDTD), which revealed that the substrate's hotspots were present in two forms: the “hotspots generated between Ag@Au nanoparticles” and the “hotspots generated between Ag@Au nanoparticles and carbon nanotubes”. These two forms of hotspots also demonstrated that the performance brought about by the preparation of the substrate structure was reliable. The simulation results were compared with the experimental results, and the analysis showed that the real environment would have an impact on the substrate's structure during the actual substrate preparation process. Finally, the substrate was used for detecting the pesticide fipronil, and the results showed clear peaks even at a concentration of 0.1 mg L−1. The results indicated that the Raman intensity was linearly exponential with the fipronil solution concentration, with a determination coefficient of R2 = 0.991. This study provides a new SERS substrate for pesticide residue detection and further explores the improvement of pesticide detection limits.
研究领域:
分析化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 19
·8867-8875
·
IF 4.197
Yu Chen,Qihua Wang,Tingmei Wang
We demonstrate the fabrication of yolk–shell catalysts consisting of a single M (M = Ag, Au) nanoparticle encapsulated within a hollow mesoporous organosilica shell via an organosilane-assisted strategy. The advantages of our method lie in its good controllability of the void space as well as the thickness of the mesoporous shell. The M@CTAB/SiO2 synthesized through a modified Stöber method can transform to yolk–shell structures after adding (3-aminopropyl)trimethoxysilane (APTMS)/TEOS or (3-aminopropyl)triethoxysilane (APTES)/TEOS into the synthetic medium. We give unambiguous evidence that the middle CTAB/SiO2 layer transforms into a less dense APTMS-rich organic–inorganic layer which was selectively removed in alkaline aqueous solution, while the amino-functionalized hybrid shells remain intact. Moreover, we discuss the role of alkylamino groups in the shell in the transformation from Ag@SiO2 nanorattles to hollow structures when impregnating the as-synthesized Ag@SiO2 nanorattles in HAuCl4 aqueous solution. The nanorattles also exhibit high catalytic activity for the catalytic reduction of p-nitrophenol.
研究领域:
材料科学
·
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2021
·
IF 5.097
Yuan Wang,Lei Feng,Haiyan Zhu,Hongyan Miao,Ying Li,Xuefeng Liu,Gang Shi
The fluorescence intensity of the ring-opened merocyanine (MC) form of spiropyran can be enhanced by metal nanostructures. However, direct contact between spiropyran and the metal results in fluorescence quenching, which will reduce the enhancement amplitude of MC fluorescence. Here, Ag nanoparticles (NPs), a TiO2 dielectric layer, a poly(methyl methacrylate)-spiropyran (PMMA-SP) layer, and Au shell-isolated NPs with SiO2 shells (Au@SiO2) are successively assembled on a Si wafer with micropyramids and nanoholes (Siph). The hierarchical structure of this substrate is similar to insects’ compound eyes with nano- and microstructures, which can reduce the reflection of incident light. Meanwhile, the Au/Ag-coupled plasmonic nanocavities can enhance the intensity of a local electromagnetic (EM) field. In addition, TiO2 and SiO2 layers can avoid the nonradiative energy transfer caused by the direct contact between spiropyan and the metal. Based on the above advantages, the fluorescence enhancement factor (EF) of this substrate is as high as 195, which is the maximum reported so far. Zn2+, Cu2+, and Sn2+ can also be detected on Siph/TiO2/PMMA-SP/Au@SiO2, whose detection limits are 0.054, 0.038, and 0.049 μM, respectively. Furthermore, this substrate can be reused to detect metal ions by taking advantage of the reversible isomerization of spiropyran. The bioinspired substrate has positive significance in improving the fluorescence intensity of MC, and its lack of specific recognition ability for metal ions is expected to be further improved by molecular modification of spiropyran.
研究领域:
材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
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