scholarly journals A Novel Electrochemical Sensor Based on Electropolymerized Ion Imprinted PoPD/ERGO Composite for Trace Cd(II) Determination in Water

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1004
Author(s):  
Jiyang Wang ◽  
Jingfang Hu ◽  
Shiwei Hu ◽  
Guowei Gao ◽  
Yu Song
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Sensor ◽  
Limit Of Detection ◽  
Experimental Conditions ◽  
Glass Carbon Electrode ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Ion Imprinted ◽  
Glass Carbon ◽  
Sensitive Determination

A novel electrochemical sensor based on electropolymerized ion imprinted poly (o-phenylenediamine) PoPD/electrochemical reduced graphene (ERGO) composite on glass carbon electrode (GCE) was fabricated for selective and sensitive determination of trace Cd(II) in water. ERGO was first deposited on the surface of GCE by electrochemical cyclic voltammetry (CV) scanning to enhance the electron transport activity at electrode surface. The ion imprinted polymer (IIP) of imprinted PoPD was then in situ electropolymerized on ERGO via CV scanning with oPD as functional monomer and Cd(II) ions as template, following removal of the template using electrochemical peroxidation method. The obtained imprinted PoPD/RERGO composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray energy spectroscopy (EDS) for the observation of their morphologies and components. The electrochemical behavior of the imprinted PoPD/ERGO/GCE was performed by CV and SWASV. The fabricated sensor of the imprinted PoPD/ERGO/GCE showed a good selectivity toward target Cd(II) ions in the presence of other heavy metal ions. Under the optimized experimental conditions, the sensor exhibited a good linear relationship between SWASV stripping peak values and Cd(II) concentration in the range of 1 to 50 ng/mL, with the limit of detection as 0.13 ng/mL (S/N = 3). The proposed electrochemical sensor of imprinted PoPD/ERGO/GCE was successfully applied for trace Cd(II) determination in real water samples.

ARCHITECTURE OF FLOWER-LIKE rGO/CNTs-LOADED CuxO NANOPARTICLES AND ITS PHOTOCATALYTIC PROPERTIES

NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350052 ◽  
Author(s):  
BIN ZENG ◽  
XIAOHUA CHEN ◽  
XUTAO NING ◽  
CHUANSHENG CHEN ◽  
HUI LONG
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Performance ◽  
Degradation Process ◽  
Photocatalytic Properties ◽  
High Concentration ◽  
Graphene Oxides ◽  
Transmission Electron ◽  
Time Scanning ◽  
Reduced Graphene ◽  
First Time

Novel flower-like composite architecture was successfully synthesized by spray drying and post-calcinating method for the first time. Scanning electron microscopy and transmission electron microscopy observations confirmed that reduced graphene oxides/carbon nanotubes hybrid (rGO/CNTs) formed a flower-like micrometer structure and Cu2O , CuO ( Cu x O , x = 1 or 2) nanoparticles were decorated inside them. The photocatalytic properties were further investigated by evaluating the photodegradation of a pollutant methyl orange (MO). The experimental results indicated that this novel architecture enhanced photocatalytic performance with 96.2% decomposition of MO after 25 min in the presence of H 2 O 2 under visible light irradiation, which was much higher than that of Cu x O powders (33.2%). This could be attributed to the more efficient adsorption of MO molecules on flower-like rGO/CNTs and provide a high concentration of MO near to the Cu x O nanoparticles, thus promoting the photocatalytic degradation process.

Molybdenum Trioxide Dihydrate-Graphene Composite for Electrochemical Detection of Thiourea Molecule

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650036 ◽  
Author(s):  
Xinmeng Zhang ◽  
Kezhi Li ◽  
Hejun Li ◽  
Jinhua Lu ◽  
Leilei Zhang
Keyword(s):  
Electrochemical Sensor ◽  
Modified Electrode ◽  
Molybdenum Trioxide ◽  
Electrochemical Sensing ◽  
Carbon Electrode ◽  
X Ray ◽  
Glass Carbon Electrode ◽  
Graphene Composite ◽  
Relative Standard ◽  
Glass Carbon

A novel electrochemical sensing platform was constructed based on a facile self-assembly procedure synthetic laminar molybdenum trioxide dihydrate (MoO[Formula: see text]H2O)-graphene composite. Field emission scanning electron microscopy (FESEM), X-ray spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy were employed to characterize the morphology and composition of the MoO[Formula: see text]H2O-graphene composite. As a model molecule, thiourea was utilized to investigate the electrochemical behaviors of the MoO[Formula: see text]H2O-graphene composite modified glass carbon electrode. The results show that the composite modified electrode has higher electron transfer rate than that of graphene modified electrode and bare glass carbon electrode meanwhile the peak currents of it has a good linear relationship with thiourea concentrations in the range of [Formula: see text] ([Formula: see text]) with detection limit of 4.99[Formula: see text][Formula: see text]M ([Formula: see text]). This novel electrochemical sensor exhibits a higher absorption capacity ([Formula: see text][Formula: see text]mol/cm2), a good reproducibility (1.41% relative standard deviation (RSD)), excellent anti-interference and a high stability. These excellent electrochemical properties of the MoO[Formula: see text]H2O-graphene composite are attributed to the loose and porous structure and the synergistic effects between graphene and MoO[Formula: see text]H2O, which make this composite material hold great potential applications for electrochemical sensor.

scholarly journals Biomass-Derived Activated Carbon as a Catalyst for the Effective Degradation of Rhodamine B dye

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 926
Author(s):  
Shamim Ahmed Hira ◽  
Mohammad Yusuf ◽  
Dicky Annas ◽  
Hu Shi Hui ◽  
Kang Hyun Park
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
High Specific Surface Area ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future.

scholarly journals Novel Nanohybrids Based on Supramolecular Assemblies of Meso-tetrakis-(4-sulfonatophenyl) Porphyrin J-aggregates and Amine-Functionalized Carbon Nanotubes

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 669 ◽  
Author(s):  
Mariachiara Trapani ◽  
Antonino Mazzaglia ◽  
Anna Piperno ◽  
Annalaura Cordaro ◽  
Roberto Zagami ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Fluorescence Emission ◽  
Resonance Light Scattering ◽  
Therapeutic Window ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
J Aggregates

The ability of multiwalled carbon nanotubes (MWCNTs) covalently functionalized with polyamine chains of different length (ethylenediamine, EDA and tetraethylenepentamine, EPA) to induce the J-aggregation of meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) was investigated in different experimental conditions. Under mild acidic conditions, protonated amino groups allow for the assembly by electrostatic interaction with the diacid form of TPPS, leading to hybrid nanomaterials. The presence of only one pendant amino group for a chain in EDA does not lead to any aggregation, whereas EPA (with four amine groups for chain) is effective in inducing J-aggregation using different mixing protocols. These nanohybrids have been characterized through UV/Vis extinction, fluorescence emission, resonance light scattering and circular dichroism spectroscopy. Their morphology and chemical composition have been elucidated through transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). TEM and STEM analysis evidence single or bundles of MWCNTs in contact with TPPS J-aggregates nanotubes. The nanohybrids are quite stable for days, even in aqueous solutions mimicking physiological medium (NaCl 0.15 M). This property, together with their peculiar optical features in the therapeutic window of visible spectrum, make them potentially useful for biomedical applications.

scholarly journals Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 666
Author(s):  
Xinchuan Fan ◽  
Yue Hu ◽  
Yijun Zhang ◽  
Jiachen Lu ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Scanning Electron

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

scholarly journals Novel Graphene/In2O3 Nanocubes Preparation and Selective Electrochemical Detection for L-Lysine of Camellia nitidissima Chi

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1999
Author(s):  
Jinsheng Cheng ◽  
Sheng Zhong ◽  
Weihong Wan ◽  
Xiaoyuan Chen ◽  
Ali Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Sensor ◽  
Chiral Recognition ◽  
Graphene Nanosheets ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Camellia Nitidissima

In this work, novel graphene/In2O3 (GR/In2O3) nanocubes were prepared via one-pot solvothermal treatment, reduction reaction, and successive annealing technology at 600 °C step by step. Interestingly, In2O3 with featured cubic morphology was observed to grow on multi-layered graphene nanosheets, forming novel GR/In2O3 nanocubes. The resulting nanocomposites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), etc. Further investigations demonstrated that a selective electrochemical sensor based on the prepared GR/In2O3 nanocubes can be achieved. By using the prepared GR/In2O3-based electrochemical sensor, the enantioselective and chem-selective performance, as well as the optimal conditions for L-Lysine detection in Camellia nitidissima Chi, were evaluated. The experimental results revealed that the GR/In2O3 nanocube-based electrochemical sensor showed good chiral recognition features for L-lysine in Camellia nitidissima Chi with a linear range of 0.23–30 μmol·L−1, together with selectivity and anti-interference properties for other different amino acids in Camellia nitidissima Chi.

Use of the curvature method to determine the misfit stress of epitaxial semiconducting systems: the case of samples thinned for TEM observation.

2003 ◽  
Vol 795 ◽  
Author(s):  
A. Ponchet ◽  
M. Cabié ◽  
L. Durand ◽  
M. Rivoal ◽  
A. Rocher
Keyword(s):  
Electron Microscopy ◽  
Mechanical Characteristics ◽  
Substrate Thickness ◽  
Element Calculation ◽  
Experimental Conditions ◽  
Misfit Stress ◽  
Reliable Determination ◽  
Substrate Side ◽  
Transmission Electron

ABSTRACTThe curvature method which allows to measure the stress in epitaxial layers has been adapted to transmission electron microscopy observations. The samples thinned by the substrate side present some particular mechanical characteristics. The ratio between the substrate thickness and the layer thickness should be taken into account. The experimental conditions allowing a reliable determination of the stress have been established. A finite element calculation has been used to show that the dimensions of the area where the measure is performed can not systematically be neglected. This method has been applied to the semiconducting systems Ga1-xInxAs/GaAs and Ga1-xInxAs/InP.

scholarly journals Facile Fabrication of CeO2/Electrochemically Reduced Graphene Oxide Nanocomposites for Vanillin Detection in Commercial Food Products

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1356 ◽  
Author(s):  
Xue Nie ◽  
Rui Zhang ◽  
Zheng Tang ◽  
Haiyan Wang ◽  
Peihong Deng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Linear Sweep Voltammetry ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide ◽  
Wide Range ◽  
Facile Fabrication

In this paper, CeO2 nanoparticles were synthesized by the solvothermal method and dispersed uniformly in graphene oxide (GO) aqueous solution by ultrasonication. The homogeneous CeO2-GO dispersion was coated on the surface of a glassy carbon electrode (GCE), and the CeO2/electrochemically reduced graphene oxide modified electrode (CeO2/ERGO/GCE) was obtained by potentiostatic reduction. The results of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) showed that CeO2 nanocrystals were uniformly coated by gossamer like ERGO nanosheets. The electrochemical behavior of vanillin on the CeO2/ERGO/GCE was studied by cyclic voltammetry (CV). It was found that the CeO2/ERGO/GCE has high electrocatalytic activity and good electrochemical performance for vanillin oxidation. Using the second derivative linear sweep voltammetry (SDLSV), the CeO2/ERGO/GCE provides a wide range of 0.04–20 µM and 20 µM–100 µM for vanillin detection, and the detection limit is estimated to be 0.01 µM after 120 s accumulation. This method has been successfully applied to the vanillin detection in some commercial foods.

scholarly journals Incorporation of reduced graphene oxide into faceted flower-like {001} TiO 2 for enhanced photocatalytic activity

2018 ◽  
Vol 5 (8) ◽  
pp. 180613 ◽  
Author(s):  
Haijin Liu ◽  
Peiyao Li ◽  
Haokun Bai ◽  
Cuiwei Du ◽  
Dandan Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Reduced Graphene Oxide ◽  
Theoretical Calculations ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Photocatalytic Activities

Anatase TiO 2 with {001} facets is much more active than that with {101} facets, which has been verified via experiments and theoretical calculations. Graphene has garnered much attention since it was initially synthesized, due to its unique properties. In this study, reduced graphene oxide (RGO)/{001} faceted TiO 2 composites were fabricated via a solvothermal method. The composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrophotometry, photoluminescence and Raman analysis. The results revealed that the graphene oxide was reduced during the preparation process of the {001} faceted TiO 2 , and combined with the surface of {001} TiO 2 . The photocatalytic activities of the composites were evaluated through the degradation of basic violet, under both white light ( λ > 390 nm) and visible light ( λ = 420 nm) irradiation. The results indicated that the photocatalytic activities of the {001} faceted TiO 2 were significantly improved following the incorporation of RGO, particularly under visible light irradiation. Theoretical calculations showed that the band structure of the {001} faceted TiO 2 was modified via graphene hybridization, where the separation of photoinduced electron–hole pairs was promoted; thus, the photocatalytic activity was enhanced.

scholarly journals A High-Response Electrochemical As(III) Sensor Using Fe3O4–rGO Nanocomposite Materials

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 150
Author(s):  
Haibing Hu ◽  
Wenjie Lu ◽  
Xingnan Liu ◽  
Fancheng Meng ◽  
Jianxiong Zhu
Keyword(s):  
Electron Microscopy ◽  
Glassy Carbon ◽  
Metal Ion ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Detection Methods ◽  
Experimental Conditions ◽  
Water Field ◽  
Conductive Substrates ◽  
Higher Sensitivity

Nowadays, heavy metal ion pollution in water is becoming more and more common, especially arsenic, which seriously threatens human health. In this work, we used Fe3O4–rGO nanocomposites to modify a glassy carbon electrode and selected square wave voltametric electrochemical detection methods to detect trace amounts of arsenic in water. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed that Fe3O4 nanoparticles were uniformly distributed on the rGO sheet, with a particle size of about 20 nm. Raman spectroscopy and electrochemical impedance spectroscopy (EIS) showed that rGO provides higher sensitivity and conductive substrates. Under optimized experimental conditions, Fe3O4–rGO-modified glassy carbon electrodes showed a higher sensitivity (2.15 µA/ppb) and lower limit of detection (1.19 ppb) for arsenic. They also showed good selectivity, stability, and repeatability.

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