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Facile Synthesis of Carbon Nanotubes Covalently Modified with ZnO Nanorods for Enhanced Photodecomposition of Dyes
摘要： Utilizing a one-pot solvothermal procedure novel one-dimensional zinc oxide-carbon nanotube nanohybrids (ZnCT) were synthesized in alcohol-alkali solution, free of catalytic assistance. The ZnCT hybrids were prepared through covalent modification of zinc oxide nanorods (ZnO NRs) with functionalized carbon nanotubes (f-CNTs). The morphology and microstructure of as-prepared ZnCT hybrids were characterized by scanning electron microscopy (SEM), powder X-ray diffraction, Raman, X-ray photoelectron and UV-vis absorption spectroscopies. SEM images of the ZnCT hybrids indicated that the ZnOethanol NRs grew longer along the vertical radial (0001) surface and aggregated to a lesser extent than the analogous ZnOmethanol NRs. Photodegradation analysis showed that the off-white ZnCTethanol hybrid with ascendant UV-visible light absorption had displayed superior photocatalytic activity towards Rhodamine B (RhB) dyes than either pure ZnOethanol, ZnOmethanol NRs or ZnCTmethanol hybrid, among which the photocatalytic activity of ZnOethanol NRs was better than that of ZnOmethanol NRs. Raman and X-ray photoelectron spectroscopy analyses confirmed a strong interaction between f-CNTs and ZnOethanol NRs in ZnCTethanol hybrid, in which Zn ions were chemically bonded to negatively charged oxygen-containing groups at the graphene-like surface of f-CNTs. The enhanced separation lifetime of the photogenerated electron-hole observed by surface photovoltage and photocurrent measurements of the ZnCTethanol hybrid was attributed to the efficient covalent linking of Zn-O-C and close contact configuration between the f-CNTs and ZnOethanol NRs. Further controlled photodegradation and electron spin resonance (ESR) analyses revealed that the photodegradation of RhB dyes resulted from photogenerated holes, and radical species, such as ?O2?、?OH?, which were formed in-situ. Details of the photocatalytic mechanism were also explored herein.
关键词： Solvothermal synthesis,ZnO nanorods,Carbon nanotubes,Dyes,Photodegradation
更新于2025-09-10 09:29:36
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Low-temperature elemental mercury removal over TiO2 nanorods-supported MnOx-FeOx-CrOx
摘要： TiO2 nanorods-supported MnOx, FeOx, CrOx, and MnOx-FeOx-CrOx catalysts have been prepared by a deposition-precipitation method, with the aim of investigating the combination of ternary metal oxides effect on elemental mercury (Hg0) removal. The TiO2 nanorods-supported MnOx-FeOx-CrOx catalyst manifested the superior Hg0 removal efficiency (~80-83%) at low temperatures (100-200°C) in the presence of O2. The addition of NO promoted the Hg0 removal efficiency under the same reaction conditions. Further, SEM, HRTEM, XRD, BET surface area, and XPS characterization were carried out to explore the physicochemical properties of the catalysts. It was found that the integration of three active metal oxides contributed to the enrichment of active sites and the surface adsorbed oxygen species, which facilitated to enhance the catalytic activity. Additionally, both the large surface area and high crystallization of the obtained TiO2 nanorods resulted in uniform dispersion of the manganese-iron-chromium mixed metal oxide nanoparticles and a high activity. Further, XPS data of spent MnOx-FeOx-CrOx/TiO2 catalyst indicated that the presence of Mn4+, Cr6+, and Fe3+ could promote Hg0 oxidation due to the strong synergistic interaction between the TiO2 nanorods-incorporated MnOx, FeOx, and CrOx nanoparticles.
关键词： Deposition-precipitation,MnOx-FeOx-CrOx,Synergistic interaction,TiO2 nanorods,Flue gas,Hg0 removal
更新于2025-09-10 09:29:36
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Preparation of Ni(OH)2/TiO2 porous film with novel structure and electrochromic property
摘要： Ni(OH)2/TiO2 nanorod composite porous film with a novel structure and remarkable electrochromic (EC) behavior was prepared on a fluorine doped tin oxide (F:SnO2; FTO) coated glass substrate by hydrothermal and solvothermal techniques. A pure Ni(OH)2 porous film was also prepared on another FTO substrate by the solvothermal technique for comparison. The growth process of Ni(OH)2 on the surface of TiO2 nanorod layer was investigated carefully. The component, morphology and microstructure of the films, as well as their EC performances including transmittance, cyclic voltammetry (CV), cycle life and response time were characterized. Compared with those of the pure Ni(OH)2 film, the EC performances of Ni(OH)2/TiO2 composite film have exhibited obvious enhancement owing to the good interface bonding, Ni(OH)2 porous structure, TiO2 nanorod layer and interpenetrating structure. Furthermore, it is noteworthy that the transmittance contrast in near infrared light area was distinctly improved, and even exceeded 95% after the 100th cycle, promising the Ni(OH)2/TiO2 nanorod composite porous film a potential EC application in near infrared light area in the future.
关键词： Composite porous film,Electrochromic property,Ni(OH)2/TiO2 nanorods,Solvothermal,Preparation
更新于2025-09-10 09:29:36
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Magnetic Supramolecular Nanofibers of Gold Nanorods for Photothermal Therapy
摘要： Molecular aggregation triggered by physical and chemical stimuli and based on multiple noncovalent interactions has immense potential utility for modeling and mimicking biological systems and for the diagnosis and treatment of degenerative diseases. Herein the preparation, properties, and biological activities of a new type of organic–inorganic hybrid supramolecular nanofiber composed of gold nanorods, mitochondrion-targeting-peptide-coated iron oxide nanoparticles, and hyaluronic-acid (HA)-modified β-cyclodextrin is reported. These photothermal nanofibers, which grew along the direction of the geomagnetic field, induced severe mitochondrial damage in human adenocarcinoma cells (A549); and, more strikingly, the nanofibers greatly suppress metastasis and clear A549 cells in tumor-bearing mice upon irradiation with a near-infrared laser. The ability to recruit HA-receptor-expressing tumor cells and to target mitochondria, as well as the high photothermal conversion efficiency imparted by the gold nanorods, makes these supramolecular nanofibers a promising nanotherapy for cancer in general and metastasis-related malignancy in particular.
关键词： gold nanorods,supramolecular nanofibers,photothermal therapy,cyclodextrin,tumor metastasis
更新于2025-09-10 09:29:36
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Photoacoustic and fluorescent effects in multilayer plasmon-dye interfaces
摘要： Progress in understanding the cell biology and progression of disease depends on advanced imaging and labeling techniques. Here, we address this demand by exploring novel multilayered nanocomposites (MNCs) with plasmonic nanoparticles and adsorbing dyes in thin nonabsorbing shells as supercontrast multimodal photoacoustic (PA) and fluorescent agents in the near-infrared range. The proof of concept was performed with gold nanorods (GNRs) and indocyanine green (ICG) dispersed in a matrix of biodegradable polymers. We demonstrated synergetic PA effects in MNCs with the gold–ICG interface that could not be achieved with ICG and GNRs alone. We also observed ultrasharp PA and emission peaks that could be associated with nonlinear PA and spaser effects, respectively. Low-toxicity multimodal MNCs with unique plasmonic, thermal, and acoustic properties have the potential to make a breakthrough in PA flow cytometry and near-infrared spasers in vivo by using the synergetic interaction of plasmonic modes with a nearby absorbing medium.
关键词： gold nanorods,fluorescence,in vivo flow cytometry,biocompatible polymers,photoacoustic effect,indocyanine green,multilayer composite,fluorescence quenching
更新于2025-09-10 09:29:36
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Gram Scale Synthesis of Isolated Monodisperse Gold Nanorods
摘要： While the gold nanorods (AuNRs) possess a strong potential application in nanotechnology, plasmonics and sensing, the scale-up synthesis of isolated AuNRs in gram quantity remains a challenge. Nearly all previously reported methods produce aqueous solutions of CTAB-coated AuNRs in milligram quantities with the yield of ~20-30 % in terms of Au (I) to Au (0) conversion. In addition, it is difficult to remove CTAB bilayer from the surface of AuNRs and yet make them soluble and functionalized for further processing and chemical modification. This report describes the synthesis of monodisperse functionalized AuNRs (σ~5%) in gram quantities. Our approach is to increase the concentration of HAuCl4.3H20 in the growth solution to produce larger quantities of starting AuNRs and further reduce the remaining Au (I) ions onto the surface of AuNRs. The slow and controlled addition of reducing agent ascorbic acid (AA) continues to Au (0) (via disproportionation reaction) onto the surface of nanorods maintaining their uniform morphology without creating any unwanted impurities of various shapes. In addition, this approach significantly narrows the size distribution due to the continuous growth of partially grown AuNRs during the initial stage of the synthesis. To isolate one-gram quantity of AuNRs and make them functionalized for further chemical reactions, a ligand exchange approach was utilized where surfactant CTAB was replaced with 4-mercaptophenol. The thiol group from 4-mercaptophenol forms a covalent bond to the surface of AuNRs leaving free functional OH groups available for further chemical coupling reactions. For the ligand exchange process, a concentrated solution of 4-mercaptophenol in tetrahydrofuran (THF) solution was introduced into the AuNRs solution. Pure AuNRs, functionalized with 4-mercaptophenol were isolated by dispersion and rinsing with excess of THF, followed by centrifugation.
关键词： Amplification,Surface Functionalization,Gram Scale,Monodisperse,Gold Nanorods
更新于2025-09-10 09:29:36
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A Depolarized Dynamic Light Scattering Method to Calculate Translational and Rotational Diffusion Coefficients of Nanorods
摘要： A new analysis of depolarized dynamic light scattering data is presented, which allows the unambiguous determination of rotational and translational diffusions coefficients of nanorods in suspension. By visualizing data scaling, purely translational diffusive motions can be isolated from vertically polarized scattering, allowing the unique determination of rotational diffusion from the depolarized scattering. The method is applied to nanorods with four different aspect ratios, and compared with theoretical predictions. Diffusion coefficients obtained show good agreement with calculations based on the direct measurements of rod length and diameter. Where the theories are shown to be valid, the method allows the measurement of statistically meaningful particle sizes and aspect ratios.
关键词： depolarized dynamic light scattering,gold nanorods,Brownian motion,translational diffusion,rotational diffusion
更新于2025-09-10 09:29:36
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Facile ionothermal synthesis of TiO2 nanorods for photocatalytic H2 generation
摘要： Facile ionothermal method has been employed to synthesize One-dimensional (1-D) mixed phase TiO2 nanorods (NRs) using ionic liquid as the reaction medium. The PXRD pattern reveals the formation of mixed phase TiO2 having 68.3% of anatase and 31.7% rutile phase with average crystallite size of ~ 10?nm. TEM images depict the average thickness of TiO2 NRs are in the range 50–100?nm. The 1-D mixed phase TiO2 NRs showed 5 times better hydrogen production activity than P-25 in the water-glycerol mixture under solar light irradiation. The reason could be the synergetic effect and unique optical properties of 1-D anatase–rutile TiO2 mixed-phase system.
关键词： solar light irradiation,TiO2 nanorods,mixed phase,ionothermal synthesis,photocatalytic H2 generation
更新于2025-09-10 09:29:36
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SERS-based lateral flow immunoassay of troponin I by using gap-enhanced Raman tags
摘要： The lateral flow immunoassay (LFIA) has emerged as a powerful tool for rapid screening owing to its simplicity and flexibility for detection of various biomarkers. However, conventional LFIA strips have several disadvantages, including limits in quantitative analysis and low sensitivity. Here we developed a novel surface-enhanced Raman scattering LFIA based on nonspherical gap-enhanced Raman tags (GERTs), with Raman molecules (RMs) embedded in a 1-nm gap between Au nanorod core and Au shell. Such tags have a strong and uniform SERS response, an order of magnitude higher than that of other common SERS tags such as Au nanorods, nanostars, Au nanoshells with surface-adsorbed RMs, or spherical GERTs with embedded RMs. The feasibility of the tags was demonstrated by the semiquantitative and sensitive detection of the heart disease biomarker cardiac troponin I (cTnI). GERTs were conjugated with monoclonal antibodies and used for LFIA in the same way as ordinary functionalized colloidal gold. The presence of the target antigen, cTnI, was identified by Raman microscopy mapping of the test zone. With the SERS-based LFIA, the limit of cTnI detection was about 0.1 ng/mL. This value is within the diagnostic range of cTnI in the blood serum of patients with heart infarction and is 30 times lower than that of the colorimetric LFIA test using the same antibodies and either GERTs or colloidal gold as labels.
关键词： gap-enhanced Raman tags,lateral flow immunoassay,SERS,cardiac Troponin I,Au core/shell nanorods
更新于2025-09-10 09:29:36
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Photoelectrochemical removal of chlorfenvinphos by using WO3 nanorods: influence of annealing temperature and operation pH
摘要： A visible-light driven photoelectrochemical degradation process has been applied to a solution polluted with the organophosphate insecticide chlorfenvinphos. Different WO3 nanosheets/nanorods have been used as photoanodes. These nanostructured electrodes have been fabricated by anodization of tungsten and, subsequently, they have been subjected to a thermal treatment (annealing). The combined influence of annealing temperature (400o C and 600o C) and operation pH (1 and 3) on the photoelectrocatalytic behavior of these nanorods has been examined through a statistical analysis. Morphological, structural and photoelectrochemical characterizations have also been carried out. The chlorfenvinphos degradation efficiency depended both on annealing temperature and, specially, operation pH. At pH 1 and using an annealing temperature of 600o C, chlorfenvinphos has been effectively degraded following pseudo-first order kinetics with a coefficient of 7.8×10-3 min-1, and notably mineralized (more than 65% of Total Organic Carbon decrease).
关键词： anodization,WO3 nanorods,chlorfenvinphos,regression model,Photoelectrochemical degradation
更新于2025-09-10 09:29:36