scholarly journals Protein-assisted scalable mechanochemical exfoliation of few-layer biocompatible graphene nanosheets

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Deepak-George Thomas ◽  
Steven De-Alwis ◽  
Shalabh Gupta ◽  
Vitalij K. Pecharsky ◽  
Deyny Mendivelso-Perez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Nanosheets ◽  
Cost Effective ◽  
X Ray Diffraction ◽  
Cytotoxic Effects ◽  
Graphene Layers ◽  
Exfoliated Graphene ◽  
Transmission Electron ◽  
Few Layer Graphene

A facile method to produce few-layer graphene (FLG) nanosheets is developed using protein-assisted mechanical exfoliation. The predominant shear forces that are generated in a planetary ball mill facilitate the exfoliation of graphene layers from graphite flakes. The process employs a commonly known protein, bovine serum albumin (BSA), which not only acts as an effective exfoliation agent but also provides stability by preventing restacking of the graphene layers. The latter is demonstrated by the excellent long-term dispersibility of exfoliated graphene in an aqueous BSA solution, which exemplifies a common biological medium. The development of such potentially scalable and toxin-free methods is critical for producing cost-effective biocompatible graphene, enabling numerous possible biomedical and biological applications. A methodical study was performed to identify the effect of time and varying concentrations of BSA towards graphene exfoliation. The fabricated product has been characterized using Raman spectroscopy, powder X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The BSA-FLG dispersion was then placed in media containing Astrocyte cells to check for cytotoxicity. It was found that lower concentrations of BSA-FLG dispersion had only minute cytotoxic effects on the Astrocyte cells.

scholarly journals Characterization and Electrochemical Behavior of Graphene-Based Anode for Li-Ion Batteries

2011 ◽  
Vol 5 (1) ◽  
pp. 236-241 ◽  
Author(s):  
Wei-Ren Liu ◽  
Shin-Liang Kuo ◽  
Chia-Yi Lin ◽  
Yi-Chen Chiu ◽  
Ching-Yi Su ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Nanosheets ◽  
Rate Capability ◽  
Reversible Capacity ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Li Ion ◽  
Synthetic Graphite ◽  
Lower Impedance ◽  
Enhanced Electrochemical Performance

In this study, we investigate the characteristics and electrochemical properties of graphene nanosheets derived from chemical-thermal exfoliation processes of SFG44 synthetic graphite (SFG44-GNS). The characterizations and electrochemical measurements were carried out by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, BET, Raman, rate capability as well as cycling tests and AC impedance. The as-synthesized SFG44-GNS with larger d-spacing of 0.3407 nm exhibits reversible capacity of 626 mAh/g and good rate capability of ~ 300 mAh/g at 2C rate, which are superior to those of graphite anode. The enhanced electrochemical performance of GNS anode was resulted from larger d-spacing, lower impedance in the interface and enhanced pore volume. The results indicate that graphene-based material is a good candidate for HEV/EV application.

scholarly journals Synthesis, Characterization and Biological Properties of Intercalated Kaolinite Nanoclays: Intercalation and Biocompatibility

2019 ◽  
Vol 19 (1) ◽  
pp. 83-99 ◽  
Author(s):  
B. Yilmaz ◽  
E. T. Irmak ◽  
Y. Turhan ◽  
S. Doğan ◽  
M. Doğan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Human Lymphocytes ◽  
Biological Properties ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Cytotoxic Effects ◽  
X Ray ◽  
Human Risk ◽  
Transmission Electron ◽  
Reflectance Ftir

AbstractThe aims of the present study were to synthesize the intercalated kaolinite samples with dimethylsulfoxide (DMSO), glutamic acid (GA), succinimide (SIM), cetylpyridiniumchloride (CPC), and hexadecyltrimethylammoniumchloride (HDTMA+); to characterize by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), and to determine the hemocompatibility and the cytotoxic effects of the intercalated kaolinite nanoclays on human lymphocytes. It was found that the intercalation with DMSO did not cause any decrease in cell viability until its maximum concentration (500 µg/mL), however, the intercalation with SIM, CPC, and (HDTMA+) causd important decreases in lymphocyte viabilities. It was determined that no significant decrease was observed in protein content of the lymphocyte cells exposed to the kaolinite nanoclays except the ones intercalated with SIM. Furthermore, the pristine kaolinite nanoclays which were intercalated with DMSO, GA, and SIM exhibited high hemocompatibility and the nanoclays intercalated with CPC and (HDTMA+) were highly hemocompatibile for the amounts below 125 and 500 µg/mL, respectively. All the results of this work can serve for the human risk assesment of intercalated nanoclays.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

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.

scholarly journals Gnidia glauca- and Plumbago zeylanica-Mediated Synthesis of Novel Copper Nanoparticles as Promising Antidiabetic Agents

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Dhiraj A. Jamdade ◽  
Dishantsingh Rajpali ◽  
Komal A. Joshi ◽  
Rohini Kitture ◽  
Anuja S. Kulkarni ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Copper Nanoparticles ◽  
Critical Role ◽  
Cost Effective ◽  
Significant Inhibition ◽  
Antidiabetic Activity ◽  
X Ray Diffraction ◽  
One Pot ◽  
Plumbago Zeylanica ◽  
Transmission Electron

Rapid, eco-friendly, and cost-effective one-pot synthesis of copper nanoparticles is reported here using medicinal plants like Gnidia glauca and Plumbago zeylanica. Aqueous extracts of flower, leaf, and stem of G. glauca and leaves of P. zeylanica were prepared which could effectively reduce Cu2+ ions to CuNPs within 5 h at 100°C which were further characterized using UV-visible spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, dynamic light scattering, X-ray diffraction, and Fourier-transform infrared spectroscopy. Further, the CuNPs were checked for antidiabetic activity using porcine pancreatic α-amylase and α-glucosidase inhibition followed by evaluation of mechanism using circular dichroism spectroscopy. CuNPs were found to be predominantly spherical in nature with a diameter ranging from 1 to 5 nm. The phenolics and flavonoids in the extracts might play a critical role in the synthesis and stabilization process. Significant change in the peak at ∼1095 cm−1 corresponding to C-O-C bond in ether was observed. CuNPs could inhibit porcine pancreatic α-amylase up to 30% to 50%, while they exhibited a more significant inhibition of α-glucosidase from 70% to 88%. The mechanism of enzyme inhibition was attributed due to the conformational change owing to drastic alteration of secondary structure by CuNPs. This is the first study of its kind that provides a strong scientific rationale that phytogenic CuNPs synthesized using G. glauca and P. zeylanica can be considered to develop candidate antidiabetic nanomedicine.

Preparation and Properties of TiO2(B)/Graphene Nanocomposites as Anode Materials Fo Lithium-Ion Batteries

2014 ◽  
Vol 875-877 ◽  
pp. 183-186 ◽  
Author(s):  
Yi Ping Tang ◽  
Shi Ming Wang ◽  
Jia Feng Ding ◽  
Guang Ya Hou ◽  
Guo Qu Zheng
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Performance ◽  
Anode Materials ◽  
Graphene Nanosheets ◽  
Coulombic Efficiency ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Graphene Nanocomposites ◽  
Transmission Electron ◽  
Uniform Diameter

In this work, TiO2(B) nanotubes with uniform diameter were prepared by the simple route of hydrothermal synthesis, and graphene nanosheets were added to form TiO2(B)/graphene nanocomposites, the two kinds of materials were comparatively studied as anode materials. The morphology and crystal structure were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The electrochemical performance was evaluated by galvanostatic chargedischarge tests. The results show that the nanocomposite electrode material has good electrochemical performance due to the contributions of graphene. At the current density of 50mA/g, the capacity of TiO2(B)/graphene is 135.8 mAh/g, and the coulombic efficiency is 61.8%, after 10 charge-discharge cycles it still retains 113.2mAh/g . However, TiO2(B) anode reduces rapidly to 65.6 mAh/g.

scholarly journals Enzyme Mimetic Activity of ZnO-Pd Nanosheets Synthesized via a Green Route

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2585 ◽  
Author(s):  
Ravi Mani Tripathi ◽  
Dohee Ahn ◽  
Yeong Mok Kim ◽  
Sang J. Chung
Keyword(s):  
Electron Microscopy ◽  
Cost Effective ◽  
Enzyme Mimics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Green Route ◽  
Protease Digestion ◽  
Recent Developments ◽  
Atomic Spacing

Recent developments in the area of nanotechnology have focused on the development of nanomaterials with catalytic activities. The enzyme mimics, nanozymes, work efficiently in extreme pH and temperature conditions, and exhibit resistance to protease digestion, in contrast to enzymes. We developed an environment-friendly, cost-effective, and facile biological method for the synthesis of ZnO-Pd nanosheets. This is the first biosynthesis of ZnO-Pd nanosheets. The synthesized nanosheets were characterized by UV–visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray. The d-spacing (inter-atomic spacing) of the palladium nanoparticles in the ZnO sheets was found to be 0.22 nm, which corresponds to the (111) plane. The XRD pattern revealed that the 2θ values of 21.8°, 33.3°, 47.7°, and 56.2° corresponded with the crystal planes of (100), (002), (112), and (201), respectively. The nanosheets were validated to possess peroxidase mimetic activity, which oxidized the 3,3′,5,5′-tetramethylbenzidine (TMB) substrate in the presence of H2O2. After 20 min of incubation time, the colorless TMB substrate oxidized into a dark-blue-colored one and a strong peak was observed at 650 nm. The initial velocities of Pd-ZnO-catalyzed TMB oxidation by H2O2 were analyzed by Michaelis–Menten and Lineweaver–Burk plots, resulting in 64 × 10−6 M, 8.72 × 10−9 Msec−1, and 8.72 × 10−4 sec−1 of KM, Vmax, and kcat, respectively.

A Facile and TGA Free Hydrothermal Synthesis of SnS Nanoparticles

NANO ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. 1750120 ◽  
Author(s):  
M. Gurubhaskar ◽  
Narayana Thota ◽  
M. Raghavender ◽  
Y. P. Venkata Subbaiah ◽  
G. Hema Chandra ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Reaction Temperature ◽  
Life Time ◽  
Cost Effective ◽  
Dual Band ◽  
X Ray Diffraction ◽  
Chloride Dihydrate ◽  
Transmission Electron ◽  
Absorber Material ◽  
Vis Spectroscopy

In this paper, we employed a simple and cost-effective thioglycolic acid (TGA) free hydrothermal method, based on thiourea hydrolysis of stannous chloride dihydrate [SnCl2.2H2O] at 160[Formula: see text]C–190[Formula: see text]C for 6[Formula: see text]h, for the synthesis of SnS nanoparticles. The effect of hydrothermal autoclave reaction temperature on various properties of SnS nanoparticles have been examined at length using X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy attached with EDAX (FE-SEM), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) spectroscopy. The results suggest that the crystallization of orthorhombic SnS nanoparticles, with size varying from 3[Formula: see text]nm to 5[Formula: see text]nm, formed at R[Formula: see text]C. Further, the formation of SnS phase was confirmed by an IR Sn-S characteristic bands around 2350[Formula: see text]cm[Formula: see text], 1041[Formula: see text]cm[Formula: see text] and 570[Formula: see text]cm[Formula: see text], and four distinguished Raman peaks at 95[Formula: see text]cm[Formula: see text], 160[Formula: see text]cm[Formula: see text], 189[Formula: see text]cm[Formula: see text] and 220[Formula: see text]cm[Formula: see text]. The mechanism for the formation of SnS nanoparticles have been proposed and discussed. The SnS nanoparticles have exhibited reaction temperature dependent morphological features like nanoflowers, nanoflakes, spherical nanoparticles and nanogranules. The absorbance studies indicated both strong direct and weak indirect allowed transitions for SnS nanoparticles and the associated band gaps were found to be 1.5[Formula: see text]eV and 1.19[Formula: see text]eV, respectively. The dual band gap combination of SnS would favor strong direct absorption of carriers and improved minority carrier life time due to indirect nature, which means the grown particles are suitable for ideal absorber material for solar cell applications.

Kinetic and structural constraints during glauconite dissolution: implications for mineral disposal of CO2

2008 ◽  
Vol 72 (1) ◽  
pp. 27-31 ◽  
Author(s):  
S. Fernandez-Bastero ◽  
C. Gil-Lozano ◽  
M. J. I. Briones ◽  
L. Gago-Duport
Keyword(s):  
Electron Microscopy ◽  
Batch Reactor ◽  
Bet Surface Area ◽  
Dissolution Mechanism ◽  
Structural Constraints ◽  
X Ray Diffraction ◽  
Ph Values ◽  
Transmission Electron ◽  
Ph Range

AbstractThe kinetics of glauconite dissolution have been determined in the pH range 2—10 (T = 25°C) using flow-batch reactor experiments. Besides the kinetic characteristics, the structural and textural aspects which could influence its long-term reactivity have also been characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and BET surface area measurements. The results from these analyses showed that glauconite follows a dual dissolution pathway which is pH-dependent, being more stable at neutral or slightly alkaline pH values. Under acidic conditions, glauconite is slightly more soluble than other ubiquitous silicates present in the marine sediments. The dissolution mechanism is incongruent at very acid pH values and tends to be congruent for intermediate and neutral ones. In addition, the results from the structural analyses suggest that the dissolution is a two-step process: the first one involves the disorder of the octahedral and tetrahedral layers, probably following a turbostratic mechanism which is evident in the XRD spectra as selective broadening of several reflections. In the second step, the dissolution of the cations from interlayer positions takes place and leads to the formation of an amorphous residue which acts as a passivating layer and reduces the reactive surface considerably. The influence of these aspects on CO2 capture via carbonation reactions is discussed.

scholarly journals Estimation of Number of Graphene Layers Using Different Methods: A Focused Review

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4590
Author(s):  
Vineet Kumar ◽  
Anuj Kumar ◽  
Dong-Joo Lee ◽  
Sang-Shin Park
Keyword(s):  
Electron Microscopy ◽  
Raman Spectra ◽  
Monolayer Graphene ◽  
Multilayer Graphene ◽  
Characterization Methods ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Stacking Order ◽  
Transmission Electron ◽  
Few Layer Graphene

Graphene, a two-dimensional nanosheet, is composed of carbon species (sp2 hybridized carbon atoms) and is the center of attention for researchers due to its extraordinary physicochemical (e.g., optical transparency, electrical, thermal conductivity, and mechanical) properties. Graphene can be synthesized using top-down or bottom-up approaches and is used in the electronics and medical (e.g., drug delivery, tissue engineering, biosensors) fields as well as in photovoltaic systems. However, the mass production of graphene and the means of transferring monolayer graphene for commercial purposes are still under investigation. When graphene layers are stacked as flakes, they have substantial impacts on the properties of graphene-based materials, and the layering of graphene obtained using different approaches varies. The determination of number of graphene layers is very important since the properties exhibited by monolayer graphene decrease as the number of graphene layer per flake increases to 5 as few-layer graphene, 10 as multilayer graphene, and more than 10 layers, when it behaves like bulk graphite. Thus, this review summarizes graphene developments and production. In addition, the efficacies of determining the number of graphene layers using various characterization methods (e.g., transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and mapping, and spin hall effect-based methods) are compared. Among these methods, TEM and Raman spectra were found to be most promising to determine number of graphene layers and their stacking order.

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