LIGHT-INDUCED AGGREGATION OF NANOPARTICLES FUNCTIONALIZED WITH 7-AMINO-4-METHYLCOUMARIN

Nano LIFE ◽  
2012 ◽  
Vol 02 (03) ◽  
pp. 1241007 ◽  
Author(s):  
JOSHUA E. ROSEN ◽  
LYNDON JONES ◽  
FRANK X. GU
Keyword(s):  
Reductive Amination ◽  
Uv Light ◽  
Synthesis Method ◽  
The Body ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Different Types ◽  
Potential Applications ◽  
Nanoparticle Formulation ◽  
Induced Aggregation

Herein, we report on the modification of silica nanoparticles with the molecule 7-amino-4-methylcoumarin (AMC) via a hydrophilic dextran linker using reductive amination chemistry. The AMC-functionalized nanoparticles were shown to aggregate in response to irradiation by 350 nm UV light. The aggregation of the particles was studied using dynamic light scattering, UV-VIS spectroscopy, and transmission electron microscopy. The synthesis method described herein utilizes a classic reductive amination reaction, which can potentially be transferred to a variety of different types of nanoparticles. Particles displaying this behavior have many potential applications in the field of nanomedicine, as they can potentially allow one to modulate the particle size of a nanoparticle formulation after administration to the body. The AMC-functionalized particles studied in this report serve as a convincing proof-of-concept for synthesizing light-responsive nanoparticles.

scholarly journals Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared CarbonaceousTiO2

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zatil Amali Che Ramli ◽  
Nilofar Asim ◽  
Wan N. R. W. Isahak ◽  
Zeynab Emdadi ◽  
Norasikin Ahmad-Ludin ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
In Situ Polymerization ◽  
Uv Light ◽  
Carbon Composite ◽  
Light Irradiation ◽  
Uv Light Irradiation ◽  
Transmission Electron ◽  
Vis Spectroscopy

This study involves the investigation of altering the photocatalytic activity of TiO2using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2(179 > 134 > 54 > 9 m2 g−1). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.

ZnS/HALLOYSITE NANOCOMPOSITES: SYNTHESIS, CHARACTERIZATION AND ENHANCED PHOTOCATALYTIC ACTIVITY

2013 ◽  
Vol 06 (02) ◽  
pp. 1350013 ◽  
Author(s):  
YI ZHANG ◽  
HUAMING YANG
Keyword(s):  
Photocatalytic Activity ◽  
Active Sites ◽  
Uv Light ◽  
Halloysite Nanotubes ◽  
Narrow Particle Size Distribution ◽  
Zns Nanoparticles ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Eosin B ◽  
Excellent Photocatalytic Activity

Zinc sulfide (ZnS) nanoparticles are successfully deposited on the surface of natural halloysite nanotubes (HNTs) to produce ZnS /HNTs nanocomposites. The samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) analysis. The results indicate that ZnS nanoparticles are uniformly attached on the surface of HNTs with narrow particle size distribution center at ~10 nm, and are prevented from aggregation by HNTs and expose more active sites. ZnS /HNTs show excellent photocatalytic activity for the degradation of eosin B under UV light, better than pure ZnS and HNTs, indicating its potential application in the field of environmental protection. The mechanism for photocatalytic activity enhancement is also investigated.

scholarly journals Zn Doped α-Fe2O3: An Efficient Material for UV Driven Photocatalysis and Electrical Conductivity

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 273 ◽  
Author(s):  
Suman ◽  
Surjeet Chahal ◽  
Ashok Kumar ◽  
Parmod Kumar
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
High Energy ◽  
Lattice Parameter ◽  
Dielectric Behavior ◽  
Energy Storage Devices ◽  
Vis Spectroscopy ◽  
Potential Applications

Zinc (Zn) doped hematite (α-Fe2O3) nanoparticles with varying concentrations (pure, 2%, 4% and 6%) were synthesized via sol-gel method. The influence of divalent Zn ions on structural, optical and dielectric behavior of hematite were studied. X-ray diffraction (XRD) pattern of synthesized samples were indexed to rhombohedral R3c space group of hematite with 14–21 nm crystallite size. The lattice parameter (a and c) values increase upto Zn 4% and decrease afterwards. The surface morphology of prepared nanoparticles were explored using transmission electron microscopy (TEM). The band gap measured from Tauc’s plot, using UV-Vis spectroscopy, showed reduction in its values upto Zn 4% and the reverse trend was obtained in higher concentrations. The dielectric properties of pure and Zn doped hematite were investigated at room temperature and followed the same trends as that of XRD parameters and band gap. Photocatalytic properties of nanoparticles were performed for hazardous Rose bengal dye and showed effective degradation in the presence of UV light. Hence, Zn2+ doped hematite can be considered as an efficient material for the potential applications in the domain of photocatalysis and also higher value of dielectric constant at room temperature makes them applicable in high energy storage devices.

scholarly journals ZnO/ZnAl2O4 Nanocomposite with 3D Sphere-Like Hierarchical Structure for Photocatalytic Reduction of Aqueous Cr(VI)

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1624 ◽  
Author(s):  
Xiaoya Yuan ◽  
Xin Cheng ◽  
Qiuye Jing ◽  
Jiawei Niu ◽  
Dong Peng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Three Dimensional ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Excellent Photocatalytic Activity ◽  
Potential Applications

Three dimensional (3D) ZnO/ZnAl2O4 nanocomposites (ZnnAl-MMO) were synthesized by a simple urea-assisted hydrothermal process and subsequent high-temperature calcination. The as-prepared samples and their precursors were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), and Photoluminescence spectra (PL). It was observed that the morphology of ZnnAl-MMO nanocomposites could be tuned from cubic aggregates, hierarchically flower-like spheres to porous microspheres by simply changing the molar ratio of metal cations of the starting reaction mixtures. The photocatalytic performance of ZnO/ZnAl2O4 nanocomposites in the photoreduction of aqueous Cr(VI) indicated that the as-prepared 3D hierarchical sphere-like ZnnAl-MMO nanocomposite showed excellent photocatalytic activity of Cr(VI) reduction under UV light irradiation. The results indicated that the maximum removal percentage of aqueous Cr(VI) was 98% within four hours at 10 mg/L initial concentration of Cr(VI), owing to the effective charge separation and diversion of photogenerated carriers across the heterojunction interface of the composite. Our study put forward a facile method to fabricate hierarchical ZnO/ZnAl2O4 composites with potential applications for wastewater treatment.

ZnS NANOFLOWERS ON GRAPHENE FOR USE AS A HIGH-PERFORMANCE PHOTOCATALYST

NANO ◽  
2014 ◽  
Vol 09 (08) ◽  
pp. 1450097 ◽  
Author(s):  
ZENG BIN ◽  
LONG HUI
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Dye Degradation ◽  
Uv Light ◽  
Xps Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Potential Applications

The nanocomposites of graphene loaded– ZnS nanoflowers (GR– ZnS ) had been successfully prepared. Materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) spectra. A possible formation mechanism of this architecture was proposed. The experimental results revealed that these nanoflowers exhibited excellent UV-light photocatalytic activities for pollutant methyl orange (MO) dye degradation. These new nanostructures were expected to show considerable potential applications in the water treatment.

Preparation and Catalytic Activity Analysis of TiO2

2012 ◽  
Vol 569 ◽  
pp. 19-22
Author(s):  
Shi Yan Han ◽  
Zhi Ming Liu ◽  
Di Wang ◽  
Ming Hua Zhu ◽  
Yan Li Ma ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Gemini Surfactant ◽  
Uv Light ◽  
Synthesis Method ◽  
Activity Analysis ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Better Than

Three kinds of TiO2 materials named Ti0, Ti0.5 and Ti1.0 were prepared via hydrothermal synthesis method using Tetrabutyl titanate (TNB) as the material and different amounts of Gemini Surfactant we prepared as the template. Then the prepared TiO2 nanoparticle was characterized by Scanning electron microscope(SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Taking the UV light as the light source ,the photocatalytic activity of TiO2 to rhB was studyed . The results showed that the degradation rate of Ti0, Ti0.5 ,Ti1.0 to RhB respectively was 93.6 % , 93.9 %, 99.7 % at the time of 3 hours. The catalytic activity of Ti0.5 and Ti1.0 was obviously better than Ti0, what’s more, Ti1.0 almost made RhB completely degradated at the time of 3 hours.

The Preparation and Photocatalytic Activity of Ni-Doped ZnS Nanoparticles

2010 ◽  
Vol 148-149 ◽  
pp. 845-848 ◽  
Author(s):  
Qiao Feng Han ◽  
Guo Zhu Diao ◽  
Xiao Heng Liu ◽  
Xin Wang
Keyword(s):  
Electron Microscopy ◽  
Uv Light ◽  
Degradation Efficiency ◽  
X Ray Diffraction ◽  
Zns Nanoparticles ◽  
X Ray ◽  
Ethyl Xanthate ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Zinc Sulfide Nanoparticles

Zinc sulfide nanoparticles as undoped and doped with nickel have been prepared by the reaction of Zn(CH3COO)2 and Ni(CH3COO)2 with potassium O-ethyldithiocarbonate (ethyl xanthate, C2H5OCS2k) at 80 in N, N - dimethylformamide (DMF) solution for 24 h. The structures of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their optical properties were studied by UV-Vis spectroscopy. The photocatalytic experiment by degrading methyl orange in aqueous solution under UV light indicated that the degradation efficiency of Ni (6%)-doped ZnS nanoparticles increased to 75% with comparison to 43% of degradation efficiency for undoped ZnS nanoparticles.

Antibody-Mediated Self-Limiting Self-Assembly for Quantitative Analysis of Nanoparticle Surfaces by Atomic Force Microscopy

2011 ◽  
Vol 17 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Carly Lay A. Geronimo ◽  
Robert I. MacCuspie
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Lower Cost ◽  
Synthesis Method ◽  
Force Microscopy ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Imaging ◽  
Induced Aggregation

AbstractQuantification of very low density molecular coatings on large (60 nm) gold nanoparticles (AuNPs) is demonstrated via the use of antibody-mediated self-limiting self-assembly of small and large AuNPs into raspberry-like structures subsequently imaged by atomic force microscopy (AFM). AFM imaging is proposed as an automated, lower-cost, higher-throughput alternative to immunostaining and imaging by transmission electron microscopy. Synthesis of large AuNPs, containing one of three ligand molecules in one of three stoichiometries (1, 2, or 10 ligands per AuNP), and small probe AuNPs with one of three antibody molecules in a one antibody per AuNP ratio, enabled a range of predicted self-limiting self-assembled structures. A model predicting the probability of observing a given small to large AuNP ratio based on a topography measurement such as AFM is described, in which random orientational deposition is assumed and which accounts for the stochastic synthesis method of the library AuNPs with varied ligand ratios. Experimental data were found to agree very well with the predictive models when using an established AFM sample preparation method that avoids drying-induced aggregation.

Rapid and Eco-Friendly Synthesis of Red Fluorescent Gold Nanoclusters for Sensing and Anti-Counterfeiting Applications

NANO ◽  
2019 ◽  
Vol 14 (09) ◽  
pp. 1950121
Author(s):  
Lei Yan ◽  
Yanlin Yu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Gold Nanoclusters ◽  
Synthesis Method ◽  
Operation Time ◽  
Experimental Conditions ◽  
Red Emission ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Mw Irradiation

A rapid and eco-friendly synthesis method for the preparation of gold nanoclusters (Au NCs) with strong red emission has been developed. A one-pot microwave (MW) irradiation method yields bright red-emitting Au NCs, providing an easy route for the synthesis of fluorescent Au NCs without the need for a tedious operation, time-consuming procedure, or the use of toxic/corrosive agents and harsh conditions. The as-prepared Au NCs show a small-sized distribution, good dispersibility and a broad excitation band (from UV light to visible light). The optimal experimental conditions, including concentrations and order of addition of Na2CO3, bovine serum albumin (BSA), and HAuCl4 and the time of MW irradiation, were investigated in detail. The as-synthesized Au NCs were well characterized by fluorescence spectroscopy, UV-Vis spectroscopy, infrared spectroscopy, high-resolution transmission electron microscopy-energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Due to favorable photoluminescence features as well as minimal toxicity, the Au NCs could be applied to sensing, patterning and anti-counterfeiting. The Au NCs displayed strong red emission that was efficiently quenched by hydrogen peroxide (H2O[Formula: see text]. More strikingly, the obtained Au NCs were used as a fluorescent ink for producing luminescent handwriting and patterns, which may expand the potential applications of Au NCs in the fabrication of security inks.

Bi-Template Assisted Sol-Gel Synthesis of Photocatalytically-Active Mesoporous Anatase TiO2 Nanoparticles

2021 ◽  
Author(s):  
Abubakar Hamisu ◽  
Umar Ibrahim Gaya ◽  
Abdul Halim Abdullah
Keyword(s):  
Electron Microscopy ◽  
Uv Light ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Hexadecyltrimethylammonium Bromide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Sol Gel Synthesis ◽  
Adsorption Desorption

Sol-gel mesoporous titanium dioxide powders have been synthesized from chitosan and/or hexadecyltrimethylammonium bromide (HDTMA) and characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and N2 adsorption-desorption measurements. The photocatalytic performance of the synthesized meso-TiO2 powders was optimized based on the central composite design (CCD) of methyl orange (MO) degradation under UV light irradiation. The maximum MO degradation was 62.3% over a period of 60 min. Oxides produced using the binary chitosan and HDTMA template (C,H-TiO2) exhibited the relatively higher surface area (99.5 m2/g), smaller crystal size (12.78 nm), narrower band-gap energy (2.92 eV) and higher photocatalytic rate constant (0.0112 min–1) than as those from chitosan (C/TiO2) or HDTMA (H/TiO2) as the template.

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