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A Multifunctional Ag/TiO <sub/>2</sub> /Reduced Graphene Oxide with Optimal Surface-Enhanced Raman Scattering and Photocatalysis
摘要： A multifunctional Ag/TiO2/reduced graphene oxide (rGO) ternary nanocomposite was prepared by a one-step photochemical reaction with TiO2 and Ag nanoparticles (NPs) successively deposited on reduced graphene oxide. The structure, morphology, composition, optical, and photoelectrochemical properties of Ag/TiO2/rGO were investigated in detail. Meanwhile, the ternary nanocomposite possessed much higher adsorption capacity to organic dyes compared with bare TiO2 and binary Ag/TiO2, which would help to its use for surface-enhanced Raman scattering (SERS) detection and photocatalytic degradation. Due to the charge transfer between rGO and organic dyes and enhanced electromagnetic mechanism (EM) of Ag, Ag/TiO2/rGO nanocomposites as surface-enhanced Raman scattering substrates demonstrated dramatically improved sensitivity and good uniformity. The detection limit of rhodamine 6G (R6G) was as low as 10-9 M, and the relative standard deviation (RSD) values of the intensities remained below 5 %. Most importantly, the synergistic coupling effect of three components extended the photoresponse range and accelerated separation of the electron-hole pairs, leading to greatly improved photocatalytic activity under simulated sunlight. The maximum rate constant (k, 0.06243 min?1) of Ag/TiO2/rGO was 50 and 4 times higher than that of TiO2 and Ag/TiO2, respectively.
关键词： SERS property,Titanium oxide,adsorption,graphene oxide,photocatalysis
更新于2025-09-04 15:30:14
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Nanopillar-Assisted SERS Chromatography
摘要： Practical implementation of surfaced enhanced Raman spectroscopy (SERS) sensing is hindered by complexity of real-life samples, which often requires long and costly pretreatment and purification. Here, we present a novel nanopillar-assisted SERS chromatography (NPC-SERS) method for simultaneous quantitation of target molecules and analysis of complex, multicomponent fluids, e.g., human urine spiked with a model drug paracetamol (PAR). Gold-coated silicon nanopillar (AuNP) SERS substrates and a centrifugal microfluidic platform are tactfully combined, which allows (i) a precise and fully automated sample manipulation and (ii) spatial separation of different molecular species on the AuNP substrate. The NPC-SERS technique provides a novel approach for wetting the stationary phase (AuNP) using the “wicking effect”, and thus minimizes dilution of analytes. Separation of PAR and the main human urine components (urea, uric acid, and creatinine) has been demonstrated. Quantitative detection of PAR with ultrawide linear dynamic range (0?500 ppm) is achieved by analyzing the spreading profiles of PAR on the AuNP surface. NPC-SERS transforms SERS into a sensing technique with general applicability, facilitating rapid and quantitative detection of analytes in complex biofluids, such as saliva, blood, and urine.
关键词： real-life samples,multicomponent analysis,quantitative SERS,full automation,nanopillar-assisted chromatography
更新于2025-09-04 15:30:14
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Ag nanoparticle decorated MnO <sub/>2</sub> flakes as flexible SERS substrates for rhodamine 6G detection
摘要： Smart design of advanced substrates for surface-enhanced Raman scattering (SERS) activity is challenging but vital. Herein, we synthesized a new kind of AgNPs/MnO2@Al flexible substrate as a SERS substrate for the detection of the analyte rhodamine 6G (R6G). The fabrication of porous MnO2 nanoflakes on Al foil was conducted via a facile hydrothermal strategy. Owing to the large active surface area of the MnO2 nanoflakes, the Ag nanoparticles were immobilized and displayed superior SERS performance with a low detection concentration of 1 × 10?6 M for R6G. In addition, the SERS performance was found to be strongly related to the morphology of the MnO2@Al substrate material. Our smart design may provide a new method of construction for other advanced SERS substrates for the detection of R6G.
关键词： Ag nanoparticles,rhodamine 6G detection,MnO2 flakes,flexible SERS substrates
更新于2025-09-04 15:30:14