scholarly journals Green Synthesis of Luminescent Gold-Zinc Oxide Nanocomposites: Cell Imaging and Visible Light–Induced Dye Degradation

2021 ◽  
Vol 9 ◽  
Author(s):  
Kanika Bharti ◽  
Shahbaz Ahmad Lone ◽  
Ankita Singh ◽  
Sandip Nathani ◽  
Partha Roy ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Visible Light ◽  
Green Synthesis ◽  
Photoelectron Spectroscopy ◽  
Sodium Citrate ◽  
Dye Degradation ◽  
X Ray ◽  
Long Duration ◽  
Solvent Free Conditions

Green synthesis of gold-zinc oxide (Au-ZnO) nanocomposite was successfully attempted under organic solvent–free conditions at room temperature. Prolonged stirring of the reaction mixture introduced crystallinity in the ZnO phase of Au-ZnO nanocomposites. Luminescence properties were observed in these crystalline Au-ZnO nanocomposites due to in situ embedding of gold nanoparticles (AuNP) of 5–6 nm diameter on the surface. This efficient strategy involved the reduction of Au(III) by Zn(0) powder in aqueous medium, where sodium citrate (NaCt) was the stabilizing agent. Reaction time and variation of reagent concentrations were investigated to control the Au:Zn ratio within the nanocomposites. The reaction with the least amount of NaCt for a long duration resulted in Au-ZnO/Zn(OH)2 nanocomposite. X-ray photoelectron spectroscopy (XPS) confirmed the formation of Zn(OH)2 and ZnO in the same nanocomposite. These nanocomposites were reconnoitered as bioimaging materials in human cells and applied for visible light–induced photodegradation of rhodamine-B dye.

scholarly journals Synthesis of Hollow Flower-Like Fe3O4/MnO2/Mn3O4 Magnetically Separable Microspheres with Valence Heterostructure for Dye Degradation

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 589 ◽  
Author(s):  
Mingliang Ma ◽  
Yuying Yang ◽  
Yan Chen ◽  
Fei Wu ◽  
Wenting Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Organic Contaminants ◽  
Dye Degradation ◽  
Catalytic Performance ◽  
X Ray ◽  
Composite Microspheres ◽  
Magnetically Separable ◽  
Mno2 Nanosheet

In this manuscript, hollow flower-like ferric oxide/manganese dioxide/trimanganese tetraoxide (Fe3O4/MnO2/Mn3O4) magnetically separable microspheres were prepared by combining a simple hydrothermal method and reduction method. As the MnO2 nanoflower working as precursor was partially reduced, Mn3O4 nanoparticles were in situ grown from the MnO2 nanosheet. The composite microspheres were characterized in detail by employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), vibration sample magnetometer (VSM) and UV–visible spectrophotometer (UV–vis). Under visible light conditions, the test for degrading rhodamine B (RhB) was used to verify the photocatalytic activity of the photocatalyst. The results showed that the efficiency of the Fe3O4/MnO2/Mn3O4 photocatalyst in visible light for 130 min is 94.5%. The catalytic activity of photocatalyst far exceeded that of the Fe3O4/MnO2 component, and after four cycles, the catalytic performance of the catalyst remained at 78.4%. The superior properties of the photocatalyst came from improved surface area, enhanced light absorption, and efficient charge separation of the MnO2/Mn3O4 heterostructure. This study constructed a green and efficient valence heterostructure composite that created a promising photocatalyst for degrading organic contaminants in aqueous environments.

scholarly journals Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
P. Nyamukamba ◽  
L. Tichagwa ◽  
S. Mamphweli ◽  
L. Petrik
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Of

Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation.

scholarly journals Duality in the Mechanism of Hexagonal ZnO/CuxO Nanowires Inducing Sulfamethazine Degradation under Solar or Visible Light

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 916 ◽  
Author(s):  
Yu ◽  
Kiwi ◽  
Wang ◽  
Pulgarin ◽  
Rtimi
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Degradation Kinetics ◽  
X Ray ◽  
Conduction Bands ◽  
Interfacial Potential ◽  
Oxidative Species ◽  
Interfacial Charge

This study presents the first evidence for the photocatalytic performance of ZnO/CuxO hexagonal nanowires leading to sulfamethazine (SMT) degradation. The chemical composition of the nanowires was determined by X-ray fluorescence (XRF). The sample with the composition ZnO/Cux = 1.25O led to faster SMT-degradation kinetics. The SMT-degradation kinetics were monitored by high performance liquid chromatography (HPLC). The morphology of the hexagonal nanowires was determined by scanning electron microscopy (SEM) and mapped by EDX. The redox reactions during SMT degradation were followed by X-ray photoelectron spectroscopy (XPS). The interfacial potential between the catalyst surface and SMT was followed in situ under solar and indoor visible light irradiation. SMT-degradation was mediated by reactive oxidative species (ROS). The interfacial charge transfer (IFCT) between ZnO and CuxO is shown to depend on the type of light used (solar or visible light). This later process was found to be iso-energetic due to the potential energy positions of ZnO and CuxO conduction bands (cb). The intervention of surface plasmon resonance (LSPR) species in the SMT degradation is discussed.

HIGHLY CATALYTIC Ag/Co3O4 NANOCATALYSTS FABRICATED FOR RhB DYE DEGRADATION THROUGH A SIMPLE SILVER-MIRROR REACTION UNDER VISIBLE LIGHT

NANO ◽  
2014 ◽  
Vol 09 (08) ◽  
pp. 1450090 ◽  
Author(s):  
XIAOLEI SI ◽  
GUANGLIANG CHEN ◽  
ZHILI CHEN ◽  
JUN HUANG ◽  
SHIHUA CHEN ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Ag Nanoparticles ◽  
Dye Degradation ◽  
Precipitation Method ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Silver Mirror ◽  
Silver Mirror Reaction

In this paper, a highly catalytic and nanosized Ag / Co 3 O 4 composite for rhodamine B ( RhB ) degradation was fabricated by using the co-precipitation method at room temperature. The Ag / Co 3 O 4 structure and catalytic properties were characterized through scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) gas-sorption measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy. The results showed that the Co 3 O 4 nanosheets prepared by hydrothermal synthesis mainly exposed (2 2 0) and (1 1 1) facets, which played an important role in determining its catalytic oxidation performance. The Co 3 O 4 nanosheets doped with Ag nanoparticles by a simple silver-mirror reaction exhibited a stable and well-dispersed property in dye solution. Compared to the Ag and Co 3 O 4 nanostructure, the Ag nanoparticles with bigger diameter (10 nm) on Co 3 O 4 surface also readily produced surface-active oxygen species and exhibited a higher catalytic activity for the degradation of RhB solution (5 mg ⋅ L-1) under the visible light. The kinetic constant K of Ag / Co 3 O 4 catalyst for RhB degradation reaction was evaluated to 0.02724 min-1, which is relatively higher than those reported in the literatures.

scholarly journals Fabrication of Zr-doped TiO2/chitosan composite catalysts with enhanced visible-light-mediated photoactivity for the degradation of Orange II dye

2018 ◽  
Vol 78 (3) ◽  
pp. 487-495 ◽  
Author(s):  
Pelin Demircivi ◽  
Esra Bilgin Simsek
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Photoelectron Spectroscopy ◽  
Dye Degradation ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Composite Catalyst ◽  
Orange Ii ◽  
X Ray ◽  
Composite Catalysts

Abstract Zirconium/titanium/chitosan (Zr/Ti/CHT) composite catalysts were synthesized by sol-gel method using different chitosan amounts (5–20 wt.%) and their activity in the photocatalytic degradation of Orange II dye was evaluated for the first time. The results were compared with Zr/Ti, Zr/CHT and Ti/CHT catalysts. The composite catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy analysis. XRD analysis revealed that the Zr/Ti/CHT composite catalyst showed high crystallinity of anatase TiO2 phase. Photocatalytic experiments showed that adding CHT into the catalyst structure increased the photocatalytic degradation under visible light irradiation. Also, the first-order reaction rate constant, kapp, was calculated using the Langmuir–Hinshelwood (L-H) equation. The kapp values were found to be 0.009, 0.0013, 0.012 and 0.014 min−1 for Zr/Ti, Zr/CHT, Ti/CHT and Zr/Ti/CHT, respectively. According to stability tests, after the first cycle Orange II dye degradation was found to be 95%, while it was 37% after the fifth cycle. The results showed that the composite catalyst could be used several times for Orange II dye degradation.

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

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