scholarly journals Simultaneous Electrochemical Detection of Nitrite and Hydrogen Peroxide Based on 3D Au-rGO/FTO Obtained Through a One-Step Synthesis

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1304 ◽  
Author(s):  
Chengcheng Li ◽  
Delun Chen ◽  
Yuanyuan Wang ◽  
Xiaoyong Lai ◽  
Juan Peng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Active Sites ◽  
Simultaneous Detection ◽  
Three Dimensional ◽  
Metal Compounds ◽  
Electrochemical Tests ◽  
Conductive Glass ◽  
Catalytic Rate Constant ◽  
One Step

In this paper, Au and reduced graphene oxide (rGO) were successively deposited on fluorine-doped SnO2 transparent conductive glass (FTO, 1 × 2 cm) via a facile and one-step electrodeposition method to form a clean interface and construct a three-dimensional network structure for the simultaneous detection of nitrite and hydrogen peroxide (H2O2). For nitrite detection, 3D Au-rGO/FTO displayed a sensitivity of 419 μA mM−1 cm−2 and a linear range from 0.0299 to 5.74 mM, while for the detection of H2O2, the sensitivity was 236 μA mM−1 cm−2 and a range from 0.179 to 10.5 mM. The combined results from scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction measurements (XRD) and electrochemical tests demonstrated that the properties of 3D Au-rGO/FTO were attributabled to the conductive network consisting of rGO and the good dispersion of Au nanoparticles (AuNPs) which can provide better electrochemical properties than other metal compounds, such as a larger electroactive surface area, more active sites, and a bigger catalytic rate constant.

Three-Dimensional Holey-Graphene Architectures for Highly Sensitive Enzymatic Electrochemical Determination of Hydrogen Peroxide

2019 ◽  
Vol 19 (11) ◽  
pp. 7404-7409 ◽  
Author(s):  
Aihua Jing ◽  
Gaofeng Liang ◽  
Hao Shi ◽  
Yixin Yuan ◽  
Quanxing Zhan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Graphene Oxide ◽  
Three Dimensional ◽  
Electrochemical Determination ◽  
High Specific Surface Area ◽  
3D Graphene ◽  
Practical Applications ◽  
Transmission Electron ◽  
Mild Defect

Three-dimensional (3D) graphene with high specific surface area, excellent conductivity and designed porosity is essential for many practical applications. Herein, holey graphene oxide with nano pores was facilely prepared via a convenient mild defect-etching reaction and then fabricated to 3D nanostructures via a reduction method. Based on the 3D architectures, a novel enzymatic hydrogen peroxide sensor was successfully fabricated. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize the 3D holey graphene oxide architectures (3DHGO). Cyclic voltammetry (CV) was used to evaluate the electrochemical performance of 3DHGO at glassy carbon electrode (GCE). Excellent electrocatalytic activity to the reduction of H2O2 was observed, and a linear range of 5.0×10-8~5.0×10-5 M with a detection limit of 3.8×10-9 M was obtained. These results indicated that 3DHGO have potential as electrochemical biosensors.

scholarly journals One-Step Acidic Hydrothermal Preparation of Dendritic Rutile TiO2 Nanorods for Photocatalytic Performance

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 683 ◽  
Author(s):  
Cheng Gong ◽  
Jun Du ◽  
Xiuyun Li ◽  
Zhenjie Yu ◽  
Jiansong Ma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Hydrothermal Method ◽  
Photocatalytic Performance ◽  
Three Dimensional ◽  
Tio2 Nanorods ◽  
Foil Surface ◽  
Rutile Tio2 ◽  
X Ray ◽  
One Step

Three-dimensional and dendritic rutile TiO2 nanorods were successfully fabricated on a Ti foil surface using a one-step acidic hydrothermal method. The TiO2 nanorods were characterized using X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and optical contact angle testing. The results showed that the nanorods with diameters of 100–500 nm and lengths of 100 nm to 1 μm were obtained on the Ti foil surface. The length and density of the TiO2 nanorods were perfect at the conditions of HCl concentration 0.5 mol/L, temperature 220 °C, and reaction time 12 h. The TiO2 nanorods formed parallel to the consumption of Ti and grew along the (110) direction having a tetragonal rutile crystal. The morphology of the nanorods possessed a three-dimensional structure. The contact angle of the nanorods was only 13 ± 3.1°. Meanwhile, the photocatalytic activities of the TiO2 nanorods were carried out using ultraviolet fluorescence spectrophotometry for the methyl orange detection, and the degradation was found to be about 71.00% ± 2.43%. Thus, TiO2 nanorods can be developed by a one-step acidic hydrothermal method using Ti foil simultaneously as the substrate with a TiO2 source; the TiO2 nanorods exhibited photocatalytic performance while being environment-friendly.

A three-dimensional multilevel nanoporous NiCoO2/Ni hybrid for highly reversible electrochemical energy storage

2019 ◽  
Vol 7 (27) ◽  
pp. 16222-16230 ◽  
Author(s):  
Binbin Liu ◽  
Jiagang Hou ◽  
Tingting Zhang ◽  
Caixia Xu ◽  
Hong Liu
Keyword(s):  
Energy Storage ◽  
Electron Transport ◽  
Active Sites ◽  
Three Dimensional ◽  
Electrochemical Energy Storage ◽  
One Step ◽  
Electrochemical Energy

A three dimensional (3D) multilevel nanoporous NiCoO2 cathode with a conductive Ni matrix is made by a one-step dealloying strategy. Benefiting from the 3D interlinking configurations for ion and electron transport, and the abundant active sites, the as-made NiCoO2/Ni cathode demonstrates superior energy storage performances.

Facile preparation of a three-dimensional macroporous graphene wrapped cuprous oxide composite by one-step hydrothermal assembly for stable and sensitive hydrogen peroxide detection

2016 ◽  
Vol 8 (40) ◽  
pp. 7405-7412 ◽  
Author(s):  
Guangran Ma ◽  
Min Yang ◽  
Guochun Zhao ◽  
Yanping Zhang ◽  
Fugang Xu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electrochemical Detection ◽  
Cuprous Oxide ◽  
Three Dimensional ◽  
One Pot ◽  
Oxide Composite ◽  
Hydrogen Peroxide Detection ◽  
One Step ◽  
Facile Preparation

A facile one-pot hydrothermal assembly approach was developed to prepare a novel three-dimensional macroporous graphene wrapped Cu2O composite (3D-p-rGO–Cu2O) for the electrochemical detection of H2O2.

One Step Synthesis of Europia Nanoparticles via Thermal Decomposition of Europium Propionate Crystals

2011 ◽  
Vol 236-238 ◽  
pp. 1799-1802
Author(s):  
Wei Fan Chen ◽  
Yong Xiu Li ◽  
Hui Quan Li
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Calcination Temperature ◽  
Three Dimensional ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Dimensional Network ◽  
One Step ◽  
Scanning Electron

Eu2O3 nanoparticles were fabricated by thermal decomposition of europium propionate crystals, which can be facilely obtained via crystallization. The decomposition and morphlogy of the crystallized product were characterized by X-ray diffractionmetry (XRD), simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) as well as scanning electron microscopy (SEM). The effects of the calcination temperature on the resultant microstructures such as crystallinity, particle size and particle dispersibility were investigated by XRD and transmission electron microscopy (TEM). The results indicated the morphology of the as-calcined products shows transmissibility compared with the precursor and that the calcination temperature of europium propionate is crucial to evolution of the resultant morphology from three-dimensional network of agglomerated nanoparticles to dispersed nanoparticles.

High-Density Implantable Microelectrode Arrays for Brain-Machine Interface Applications

2014 ◽  
Vol 96 ◽  
pp. 95-101 ◽  
Author(s):  
Bahareh Ghane-Motlagh ◽  
Mohamad Sawan
Keyword(s):  
Active Sites ◽  
Three Dimensional ◽  
Microelectrode Arrays ◽  
Biological Response ◽  
High Density ◽  
Process Time ◽  
Coating Materials ◽  
Neural Tissues ◽  
One Step ◽  
Silicon Based

Microelectrode arrays (MEAs) act as an interface between electronic circuits and neural tissues of implantable devices. Biological response to chronic implantation of MEAs is an essential factor in determining a successful electrode design. Finding appropriate coating materials which are biocompatible and improve electrical properties of MEAs are among the main challenges. In this paper, we propose a novel, three-dimensional (3D), high-density, silicon-based MEAs for both neural recording and stimulation. Electrodes were fabricated using micromachining techniques. Geometrical features of these electrodes not only cause less tissue damage during insertion but also provide more contacts between the electrodes and targeted neural tissues. In order to achieve the proposed geometry, we introduce a novel masking method to coat variable-height electrodes with uniform and small tip-exposure. More importantly, compared to conventional techniques, the new masking method significantly improves process time and costs. This technique needs only one step masking and reduces the conventional masking steps from ten to three. In the next step, the active sites of the electrodes were coated with thin-films of molybdenum (Mo) and platinum (Pt) due to their ability to transfer between ionic and electronic current and to resist corrosion. Electrodes were characterized by scanning electron microscopy and impedance measurements. The average impedance of Mo and Pt electrodes at 1 kHz was 350 ± 50 kΩ and 150 ± 10 kΩ, respectively.

scholarly journals A Novel Nanocomposite of Activated Serpentine Mineral Decorated with Magnetic Nanoparticles for Rapid and Effective Adsorption of Hazardous Cationic Dyes: Kinetics and Equilibrium Studies

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 684 ◽  
Author(s):  
Moaaz K. Seliem ◽  
Mariusz Barczak ◽  
Ioannis Anastopoulos ◽  
Dimitrios A. Giannakoudakis
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Environmental Remediation ◽  
Electrostatic Interactions ◽  
Active Sites ◽  
Eastern Desert ◽  
Cationic Dyes ◽  
Significant Deterioration ◽  
Equilibrium Studies ◽  
The Difference

A widely distributed mineral, serpentine, obtained from Wadi Ghadir (Eastern Desert in Egypt) was studied as a potential naturally and abundantly available source for the synthesis of an efficient adsorbent for aquatic remediation applications. A novel nanocomposite was synthesized after the exfoliation of the layered structure of serpentine by hydrogen peroxide treatment (serpentine (SP)), followed by decoration with magnetic Fe3O4 nanoparticles (MNP). The goal behind the utilization of the latter phase was to increase the environmental remediation capability and to incorporate magnetic properties at the final adsorbent, toward a better separation after the use. The fabricated composite (MNP/SP) was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The composite’s potential adsorption application toward the removal of two cationic dyes, methylene blue (MB) and malachite green (MG), was investigated. The observed adsorption kinetics was fast, and the highest uptake was observed at pH = 8, with the capacities to reach 162 and 176 mg g−1 for MB and MG, respectively, values significantly higher than various other materials tested against these two cationic dyes. Compared to hydrogen peroxide-treated serpentine, the removal efficiency of the composite was higher by 157 and 127% for MB and MG, respectively. The MB and MG were adsorbed because of the favorable electrostatic interactions between MNP/SP active sites and the cationic dyes. The close value capacities suggest that the difference in chemistry of the two dyes does not affect the interactions, with the later occurring via the dyes’ amine functionalities. With increasing ionic strength, the adsorption of the studied basic dyes was slightly decreased, suggesting only partial antagonistic ion effect. The sorbent can be easily regenerated and reused without significant deterioration of its adsorption efficiency, which makes MNP/SP a promising adsorbent for the removal of hazardous pollutants from aquatic environments.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

Three-Dimensional Visualization of the T-System of Frog Muscle Using High Voltage Electron Microscopy and a Lanthanum Stain

1977 ◽  
Vol 35 ◽  
pp. 570-571 ◽  
Author(s):  
Lee D. Peachey ◽  
Clara Franzini-Armstrong
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Three Dimensional ◽  
Biological Tissues ◽  
High Voltage Electron Microscopy ◽  
Transverse Tubular System ◽  
Peroxidase Reaction ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
T System

The effective study of biological tissues in thick slices of embedded material by high voltage electron microscopy (HVEM) requires highly selective staining of those structures to be visualized so that they are not hidden or obscured by other structures in the image. A tilt pair of micrographs with subsequent stereoscopic viewing can be an important aid in three-dimensional visualization of these images, once an appropriate stain has been found. The peroxidase reaction has been used for this purpose in visualizing the T-system (transverse tubular system) of frog skeletal muscle by HVEM (1). We have found infiltration with lanthanum hydroxide to be particularly useful for three-dimensional visualization of certain aspects of the structure of the T- system in skeletal muscles of the frog. Specifically, lanthanum more completely fills the lumen of the tubules and is denser than the peroxidase reaction product.

Electron Microscopy of Cytoplasmic Contractile Proteins

1978 ◽  
Vol 36 (3) ◽  
pp. 606-614 ◽  
Author(s):  
T.D. Pollard ◽  
P. Maupin
Keyword(s):  
Electron Microscopy ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Uranyl Acetate ◽  
Contractile Proteins ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Cytoplasmic Matrix ◽  
Computer Image Processing ◽  
Nonmuscle Cells

In this paper we review some of the contributions that electron microscopy has made to the analysis of actin and myosin from nonmuscle cells. We place particular emphasis upon the limitations of the ultrastructural techniques used to study these cytoplasmic contractile proteins, because it is not widely recognized how difficult it is to preserve these elements of the cytoplasmic matrix for electron microscopy. The structure of actin filaments is well preserved for electron microscope observation by negative staining with uranyl acetate (Figure 1). In fact, to a resolution of about 3nm the three-dimensional structure of actin filaments determined by computer image processing of electron micrographs of negatively stained specimens (Moore et al., 1970) is indistinguishable from the structure revealed by X-ray diffraction of living muscle.

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