Journal of Nanoscience and Nanotechnology
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21491
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Published By American Scientific Publishers

1533-4880

2021 ◽  
Vol 21 (12) ◽  
pp. 6073-6081
Author(s):  
Qian Zhang ◽  
Bingxin Wang ◽  
Jun-Ming Hong

The application of electrochemical catalytic oxidation in wastewater treatment with powerful Cldoped graphene as an anode has been discussed as a novel approach to degrade acetaminophen effectively. The characteristics of Cl-doped graphene that were related to Cl loading content and microscopic morphology were analyzed by using several instruments, and the defects created by Cl doping were identified. Quenching experiments and electron paramagnetic resonance detection were proposed to clarify the mechanism underlying the production of active free radicals by Cldopedgraphene. The degradation results indicated that efficiency increased with the percentage of Cl atoms doped into the graphene. The best degradation efficiency of acetaminophen could reach 98% when Cl-GN-12 was used. In the process of electrocatalytic oxidation, O•−2, and active chlorine, as the main active species, persistently attacked acetaminophen into open-ring intermediates, such as 4-chlororesorcinol, and finally into CO2 and H2O.


2021 ◽  
Vol 21 (12) ◽  
pp. 5835-5845
Author(s):  
Ranjith Balu ◽  
Arivuoli Dakshanamoorthy

Supercapacitor with high specific capacity is desirable for various energy storage and high powerdensity applications. Though Graphene has been the preferred material for high current density, nanocomposites have been attempted to increase the specific capacitance. Hydrothermal synthesis of cadmium sulfide/graphene (CdS/G) nanocomposite with CdS nanoparticles anchored/decorated over the graphene sheets is reported. The structural studies reveal the hexagonal phase of the prepared materials. The specific surface area (BET) and porosity is found to increase upon nanocomposite formation. The electrochemical characteristics such as cyclic voltammetry (CV), GCD and EIS of the CdS/G nanocomposite have been investigated. The capacitance of CdS/G nanocomposite almost doubled to 248 Fg−1 indicating the enhanced performance of the nanocomposite system and in addition it also showed excellent cycling stability of 74.8 percent after 1000 cycles. The supercapacitor investigated retained the initial energy density after charge-discharge, at 0.5 A/g for 1000 cycles. The graphene nanosheets increased the specific surface area and interfacial electron transfer of the composite material. It enhances the specific capacitance and cyclic stability of the supercapacitor device.


2021 ◽  
Vol 21 (12) ◽  
pp. 5846-5858
Author(s):  
Yun Ding ◽  
Mingxia Tian ◽  
Aili Wang ◽  
Hengbo Yin

Expanded graphite and graphite nanosheets were facilely prepared by the thermal expansion of expandable graphite at 800 °C and sand milling of expanded graphite in water, respectively. When the expandable graphite precursor was prepared by the oxidation and intercalation of natural graphite (5 g) using KMnO4 (6 g) as an oxidant in a concentrated sulfuric acid solution (120 mL) at room temperature (25 °C) for 8 h, the expanded graphite with a maximum volumetric rate of 317 mL g−1 was prepared after the thermal expansion of the expandable graphite precursor at 800 °C for 60 s. The oxidation extent of natural graphite with KMnO4 is crucial for the preparation of expanded graphite. The thicknesses of graphite nanosheets decreased from 8.9 to 3.2 nm when the sand milling time of the expanded graphite in deionized water was prolonged from 6 to 24 h. The prolonging of the sand milling time not only decreased the layer number of the graphite nanosheet but also increased the d002 spacing due to the shocking and shearing forces. The addition of the expanded graphite powder and graphite nanosheets in a polyester paint efficiently improved the electrical conductivity of the resultant polyester coating films.


2021 ◽  
Vol 21 (12) ◽  
pp. 6160-6167
Author(s):  
Sakthivel Kumaravel ◽  
Sivakumar Thiripuranthagan ◽  
Elangovan Erusappan ◽  
Aishwarya Sivakumar ◽  
Saranraj Kumaravel ◽  
...  

Pristine TiO2 and x% Ru/TiO2 catalysts with different wt.% of Ru (x%= 1.5%, 2%, 2.5% and 3%) were synthesized using sol–gel and simple impregnation methods. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), High-resolution transmission electron microscope (HR-TEM), Inductively coupled plasma-optical emission spectrometry (ICP-OES) and Thermogravimetry/Differential thermal analysis (TG/DTA) were used to study the physicochemical and morphological properties. The XRD patterns of the as-prepared pristine TiO2 catalyst showed high crystalline nature. The HR-TEM images revealed that the Ru nanoparticles (NPs) were evenly dispersed on the TiO2 surface. The prepared catalysts were evaluated for their catalytic activity towards the liquid phase hydrogenation of ethyl levulinate under mild reaction conditions (ambient H2 pressure). Among the various catalysts, 2.5% Ru/TiO2 catalyst showed the maximum catalytic activity of 79% ethyl levulinate (EL) conversion with 82% selectivity of γ-valerolactone (GVL). The recyclability test revealed that the most active 2.5% Ru/TiO2 also showed the highest stability of the catalyst under optimized experimental conditions.


2021 ◽  
Vol 21 (12) ◽  
pp. 6101-6110
Author(s):  
Dong Sun ◽  
Shu-Jun Li ◽  
Chun-Feng Wang ◽  
Tian-Tian Liu ◽  
Guang-Yue Bai ◽  
...  

Innovative nitrogen and boron co-doped carbon dots are hydrothermally produced using fructose, urea, and boric acid as precursors. The synthesized carbon dots possess a uniform morphology, and exhibit excellent fluorescence stability, tunable luminescence property, strong resistance to photobleaching, low-toxicity, and excellent biocompatibility. It is also found more dopant urea is conducive to the formation of the carbon dots with more B–N bonds, and shorter wavelength of fluorescence emission. Meanwhile, the synthesized carbon dots are well utilized as a photoluminescent probe for facile Hg2+ determination and fluorescent imaging reagent in cells.


2021 ◽  
Vol 21 (12) ◽  
pp. 6054-6059
Author(s):  
Yuelan Liang ◽  
Ya-Nan Chang ◽  
Xue Li ◽  
Ziteng Chen ◽  
Jiaxin Zhang ◽  
...  

Enhanced permeation and retention (EPR) effect, the mechanism by which nanodrugs accumulate in tumors and acquire superior curative effect. The questions of these mechanisms occur because of limited clinical transformation of engineered nanomaterials after 30 years. The difference of EPR limits the therapeutic effect of nanodrugs in the individual patient. Evaluation of the EPR effect in the individual patient will aid in selecting patients who will accumulate higher amounts of nanotherapeutics and show better therapeutic efficacy. Based on varied TIMP1/MMP-9 in serum, an aggregation-induced emission luminogen probe was designed and constructed to detect and evaluate the EPR effect in model mouse. The result showed that the ratio of TIMP1/MMP-9 (in the range 0.2–1.2) and fluorescence intensity of the probe were negative linear correlation and the effects of BSA-rhodamine accumulation in tumor were individualized differences as well as correlated with the relative ratio of TIMP-1/MMP-9 in serum. Our data support the development of these biomarkers probes based on the personalized nanotherapy of tumor.


2021 ◽  
Vol 21 (12) ◽  
pp. 5859-5866
Author(s):  
Jian Zhou ◽  
Si-Li Ren

Various Eu2+-based Ca9Nd(PO4)7 (CNP:xEu2+, with different x values) materials are prepared via facile solid-state reaction. Their crystal structures are investigated in detail by means of the Rietveld refinement. The structure of CNP:Eu2+ with a trigonal lattice is analogous to that of β-Ca3(PO4)2. Therefore, Eu2+ ions tend to incorporate calcium sites in the host. All the obtained samples can be excited using near ultraviolet (nUV) light to present blue-green emission. An optimal dopant concentration is verified at x = 0.8 with a large critical interaction radius (11.21 Å). The mechanism of the concentration quenching effect is assigned to the multipole-multipole interaction. CNP:xEu2+ possesses a short decay lifetime of ∼60 μs and can endure severe working conditions thanks to its great thermal stability. The relative photoluminescence (PL) intensity of CNP:0.8Eu2+ can retain 84.75% of the pristine intensity measured at room temperature, and the relative intensity remains as high as 69.97% at 423 K. The CNP:Eu2+ phosphors also show great performance in the WLED demonstration. The correlated color temperature (CCT) of the prototype device is 3404 K, with an extremely high Ra (97.6). Therefore, CNP:xEu2+ could be regarded as a promising alternative to blue green phosphors in nUV chip-based WLED applications.


2021 ◽  
Vol 21 (12) ◽  
pp. 6196-6204
Author(s):  
Shu Wen ◽  
Weiping Xing ◽  
Lingxue Gao ◽  
Shuping Zhao

This study aimed to investigate the effects of DMSO@γ-Fe2O3 nanomagnetic fluid thermotherapy combined with the chemotherapy drug carmustine on cervical cancer cells under a certain intensity of alternating magnetic field. And the role of Mir-590-3P in the development and progression of cervical cancer. The optimal thermotherapy concentration of γ-Fe2O3 nanomaterials on cervical cancer cells was determined by in vitro heating. In addition, the MTT colorimetric method was used to evaluate the toxic effect of γ-Fe2O3 magnetic nanoparticles on cervical cancer cells, and the optimal therapeutic concentration of carbachol on cervical cancer cells was optimized (0.015 g · L−1). The cervical cancer cells were divided into control, γ-Fe2O3 hyperthermia, chemotherapy, and DMSO@γ-Fe2O3 combined chemotherapy groups. After 2 h exposure to hypothermic conditions, flow cytometry was used to assess cell apoptosis for each group. The heating effect of the γ-Fe2O3 magnetic nanomaterials was apparent. When the concentration of γ-Fe2O3 was ≥6 g· L−1, the temperature rise above 41 °C. γ-Fe2O3 is non-toxic to cervical cancer cells and has good biocompatibility. Taking the drug concentration of IC25 as the working concentration of this study, the working concentration of carmustine was 0.015 g · L−1. Both the 41 °C heat treatment and chemotherapy alone had a killing effect on glioma and cervical cancer cells (P < 0.05). Additionally, the combined inhibitory effect of DMSO@γ-Fe2O3 nanomagnetic fluid thermotherapy and drugs at this temperature was significantly stronger than that of thermotherapy and chemotherapy alone (P < 0.05). For the control, gamma-Fe2O3 hyperthermia, chemotherapy, and DMSO@γ-Fe2O3 combined chemotherapy groups, the apoptosis rates of the cervical cancer cells were 1.4%, 18.6%, 24.12%, and 38.97%, respectively. DMSO@γ-Fe2O3 nanomagnetic fluid thermotherapy combined with the chemotherapeutic drug carmustine exerted a noticeable toxic effect on the cervical cancer cells, and DMSO@γ-Fe2O3 significantly enhanced the killing effect of carmustine on cervical cancer cells.


2021 ◽  
Vol 21 (12) ◽  
pp. 5960-5964
Author(s):  
Kwon Jai Lee ◽  
Jee Young Oh ◽  
Kyong Nam Kim

With the rapid development of the electronics industry, high-density electronic devices and component mounting have gained popularity. Because of the heat generated from these devices, efficiency of the electronic parts is significantly lowered and life of various electronic devices is considerably shortened. Therefore, it is essential to efficiently dissipate the heat generated from the device to extend product life and ensure high efficiency of electronic components. This study evaluated how residual stress is impacted by the thickness of the deposited copper film, which is widely used as a heat dissipation material, and the number of graphene layers. The results confirmed that the residual stress decreased with increasing thickness. Moreover, the residual stress changed based on the transfer area of graphene, which had an elastic modulus eight times that of copper, indicating that the residual stress of the deposited copper film can be controlled.


2021 ◽  
Vol 21 (12) ◽  
pp. 5795-5811
Author(s):  
Milan Z. Momčilović ◽  
Jelena S. Milićević ◽  
Marjan S. Ranđelović

Widespread usage of pesticides in agricultural practice caused their residues to appear in water and food products intended for human consumption. The potential toxicity of these resources has raised awareness about pesticide tracking in the environment. Development of reliable electrochemical sensors for the on-site determination of pesticide concentrations is envisioned as an alternative to conventional chromatographic methods which are robust, expensive and require skilled work force. Modification of the working electrode surface can result in enhanced electrochemical response towards selected pesticide making such electrode convenient sensor for facile and efficient determination of pesticides in low concentrations. New generation of nanomaterials is applied in electrode modification in order to improve its sensitivity and selectivity. The present review summarizes significant advances in voltammetric detection of pesticides for the period of the past five years. The major focus of this review is set to the types of carbon and oxide based materials, metal nanoparticles, composites and other materials employed to upgrade standard electrode configurations such as glassy carbon and carbon paste electrodes, boron doped diamond electrodes, screen printed and film electrodes, metal and amalgam, and other kinds of electrodes.


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