scholarly journals High-Efficiency Production of Large-Size Few-Layer Graphene Platelets via Pulsed Discharge of Graphite Strips

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1785 ◽  
Author(s):  
Xin Gao ◽  
Tomomasa Hiraoka ◽  
Shunsuke Ohmagari ◽  
Shigeru Tanaka ◽  
Zemin Sheng ◽  
...  
Keyword(s):  
High Efficiency ◽  
Expanded Graphite ◽  
Cost Effective ◽  
High Yield ◽  
Pulsed Discharge ◽  
Force Microscopy ◽  
Large Size ◽  
Potential Applications ◽  
Graphene Platelets ◽  
Few Layer Graphene

The synthesis of large-size graphene materials is still a central focus of research into additional potential applications in various areas. In this study, large-size graphene platelets were successfully produced by pulsed discharge of loose graphite strips with a dimension of 2 mm × 0.5 mm × 80 mm in distilled water. The graphite strips were made by pressing and cutting well-oriented expanded graphite paper. The recovered samples were characterized by various techniques, including TEM, SEM, optical microscopy (OM), atomic force microscopy (AFM), XRD and Raman spectroscopy. Highly crystalline graphene platelets with a lateral dimension of 100–200 μm were identified. The high yield of recovered graphene platelets is in a range of 90–95%. The results also indicate that increasing charging voltage improves the yield of graphene platelets and decreases the number of graphitic layers in produced graphene platelets. The formation mechanism of graphene platelets was discussed. This study provides a one-step cost-effective route to prepare highly crystalline graphene platelets with a sub-millimeter lateral size.

Millimetre-scale growth of single-wall carbon nanotube forests using an aluminium nitride catalyst underlayer

MRS Advances ◽  
2019 ◽  
Vol 4 (3-4) ◽  
pp. 177-183
Author(s):  
Takashi Tsuji ◽  
Naoyuki Matsumoto ◽  
Hirokazu Takai ◽  
Shunsuke Sakurai ◽  
Don N. Futaba
Keyword(s):  
Carbon Nanotube ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Ostwald Ripening ◽  
Average Diameter ◽  
Aluminium Nitride ◽  
High Yield ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Carbon Nanotube Forests

ABSTRACTWe have demonstrated the high yield (∼900 μm) and highly single-wall selective (>95%) growth of carbon nanotube (CNT) forest using aluminium nitride (AlN) as a catalyst underlayer. Such high efficiency and single-wall selectivity have not been previously reported using this underlayer system. Evaluation with transmission electron microscopy showed that the average diameter of the grown carbon nanotubes was ∼3.0 nm, which is similar to those grown on alumina underlayers. In addition, characterization of the catalyst/underlayer system using atomic force microscopy and X-ray photoelectron spectroscopy suggests that neither Ostwald ripening along the surface nor catalyst subsurface diffusion into the AlN underlayer are severely occurring at the growth temperature, leading to the creation of the stable and dense small nanoparticle array to achieve an efficient growth of single-wall CNTs.

Synthesis and Characterization of Graphene Sheets from Graphite through Electrochemical Exfoliation and Microwave Reduction

2021 ◽  
Vol 875 ◽  
pp. 127-137
Author(s):  
Arshad Hussain Wazir ◽  
Imran Waseem Kundi ◽  
Wahib Noor Khan ◽  
Abdul Manan ◽  
Imdadullah Querashi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Microwave Irradiation ◽  
Uv Spectra ◽  
High Yield ◽  
Graphene Sheets ◽  
X Ray ◽  
Force Microscopy ◽  
Exfoliated Graphene ◽  
The Difference ◽  
Few Layer Graphene

Graphene as a wonder material has received great attention and importance due to its fascinating properties. Here in this study, we also demonstrate a simple two step process to prepare graphene sheets (GSs) from the electrochemical exfoliated graphene oxide (EE-GO) followed by microwave irradiation reduction. The properties and structure of the resulted product samples were studied by Ultraviolet spectroscopy (UV), Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX or EDS), Raman spectroscopy and Atomic force microscopy (AFM) for validation of their distinguishing characteristics. UV spectra of microwave irradiation reduced graphene oxide (MI-RGO) and EE-GO exhibited an intense and sharp absorption peak concentrated at wavelengths of 236 and 266nm, respectively. The elimination of oxygen functionalities present in the EE-GO plane was illustrated by FTIR as a result of microwave irradiation treatment. The relative layer structures of MI-RGO and EE-GO were confirmed by XRD. Similarly, the Raman spectra revealed the difference in between the EE-GO and MI-RGO characteristic reflection bands. The thin, crumpled and curved type morphology of the obtained graphene sheets (GSs) was also displayed by SEM while the composition of a few layer graphene sheets with atomic mass percents of carbon (75%) and oxygen (25%) was established by EDX. The Synthesis procedure is simple, rapid and eco-friendly with high yield.

scholarly journals A new process of smelting laterite by lowtemperature reduction and microwave irradiation

2019 ◽  
Vol 277 ◽  
pp. 01001
Author(s):  
Lei Wang ◽  
Peimin Guo ◽  
Lingbing Kong
Keyword(s):  
Microwave Irradiation ◽  
High Efficiency ◽  
Nickel Content ◽  
Reduction Reaction ◽  
Smelting Process ◽  
High Yield ◽  
Large Size ◽  
New Process ◽  
Fundamental Research ◽  
Annual Capacity

A new smelting process for the reduction of laterite with a relatively high yield of Ni has been presented in this paper; particularly, this process has been underwent industrialized experiment in China. This new process was based on the following fundamental research results. (1) Since nickel oxide can be reduced more easily than iron oxide, the nickel content of the produced ferronickel alloy increases significantly when the quantity of coal that is mixed with laterite ore is optimized, leading to a right oxygen potential of gas for reduction reaction. (2) When laterite is reduced at 1150°C, only 75% of the reduced ferronickel product can be magnetically separated from slag, although more than 95% Ni has been reduced from laterite. (3) The key technology is to realize a fast carburization at 1300°C by microwave irradiation, which causes ferronickel fines grow to a large size in the semi-melting state so that they can be separated magnetically with a high efficiency. The first demonstration production line with an annual capacity of 100 kt green balls has been established in China. The Ni content reaches 13.5%, moreover, both P and S contents are also within the expected range.

scholarly journals High-Yield Production of Few-Layer Graphene via New-fashioned Strategy Combining Resonance Ball Milling and Hydrothermal Exfoliation

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 667 ◽  
Author(s):  
Qingfeng Yang ◽  
Ming Zhou ◽  
Mingyang Yang ◽  
Zhixun Zhang ◽  
Jianwen Yu ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrothermal Treatment ◽  
Electrochemical Sensors ◽  
High Yield ◽  
Scale Production ◽  
Step Method ◽  
Functional Coating ◽  
Layer Graphene ◽  
Potential Applications ◽  
Few Layer Graphene

Graphene shows great potential applications in functional coating, electrodes, and ultrasensitive sensors, but high-yield and scalable preparation of few-layer graphene (FLG) by mechanical exfoliation method is still a formidable challenge. In this work, a novel two-step method for high-yield preparation of FLG is developed by combining resonance ball milling and hydrothermal treatment. During the resonance ball milling process, the utilization of magnetic Fe3O4 nanoparticles as a new “particle wedge” is beneficial to facilitate fragment and delamination of graphitic layers. In addition, further hydrothermal treatment can enhance ball milling product (BMP) exfoliation because of the shear force driven by the Brownian motion of various molecules at high temperature and high pressure. As expected, the two-step method can have high exfoliation efficiency up to 92% (≤10 layers). Moreover, the FLG nanosheet ink can easily achieve the formation of FLG coatings on the surface of various substrates, resulting in good electrical conductivity, which possesses potential applications in various fields including functional coating, energy storages, and electrochemical sensors, etc. Our work provides a new-fashioned strategy for mechanical large-scale production of graphene.

Simple, Fast and Cost-Effective Electrochemical Synthesis of Few Layer Graphene Nanosheets

NANO ◽  
2015 ◽  
Vol 10 (02) ◽  
pp. 1550019 ◽  
Author(s):  
Sumanta Kumar Sahoo ◽  
Archana Mallik
Keyword(s):  
Graphene Nanosheets ◽  
Pyrolytic Graphite ◽  
Cost Effective ◽  
Graphite Sheet ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Green Approach ◽  
Atomic Force ◽  
Absorbance Peak ◽  
Few Layer Graphene

We report an efficient and green approach for mass production of few layered graphene nanosheets (FLGNSs) by intercalation and exfoliation of pyrolytic graphite sheet in a simple protic, H 2 SO 4 electrolyte. The as-prepared FLGNSs at the optimum intercalate concentration of 0.5 M H 2 SO 4 is able to produce large domain of lateral dimension of 11–26 μm consisting of 4–6 stacked graphene layers, as confirmed by field emission scanning electron microscopy and atomic force microscopy, respectively. Surface oxygenation and a characteristic absorbance peak at 228 nm are well observed for electrochemical exfoliated FLGNSs from Fourier transform infrared spectroscopy and UV–Vis spectra respectively. (002) planes of the obtained graphene sheets have been confirmed from X-ray diffraction pattern. The characteristic Raman bands have been observed at 1354 cm-1 and 1590 cm-1 in the exfoliated FLGNSs.

Heteroepitaxy and Waveguide Formation for Solution Deposited LiNbO3 Thin Layers

1995 ◽  
Vol 392 ◽  
Author(s):  
P. G. Clem ◽  
D. A. Payne
Keyword(s):  
High Efficiency ◽  
Second Harmonic ◽  
Proton Exchange ◽  
Thin Layers ◽  
Solution Deposition ◽  
Factors Affecting ◽  
Force Microscopy ◽  
Atomic Force ◽  
Potential Applications ◽  
Channel Waveguides

AbstractLithium niobate thin layers have potential applications in integrated, high efficiency signal modulators, and in second harmonic generation devices. We report the solution deposition of heteroepitaxial LiNbO3 thin layers on (006), (110) and (012) sapphire. Factors affecting surface roughness were investigated by atomic force microscopy. The best results for optical losses occurred after fresh, 0.1M unhydrolyzed solutions were used. Channel waveguides were developed by lithography and proton exchange. Waveguides were formed in Nd3+- and Er3+-doped thin layers to confine light and assess the possibility of integrated waveguide lasers.

scholarly journals Bacillus methylotrophicus has potential applications against Monilinia fructicola

2019 ◽  
Vol 14 (1) ◽  
pp. 410-419 ◽  
Author(s):  
Xue Yuan ◽  
Xu Hou ◽  
Haotian Chang ◽  
Rui Yang ◽  
Fang Wang ◽  
...  
Keyword(s):  
Cost Effective ◽  
High Yield ◽  
Inhibition Rate ◽  
Sequencing Data ◽  
Bacillus Methylotrophicus ◽  
Tem Cell ◽  
Potential Applications ◽  
Physiological Analysis ◽  
Peach Trees ◽  
Intracellular Vacuole

AbstractBiocontrol is a cost-effective and environmentally friendly technique used in agricultural production. We isolated and screened a bacterial strain from the soils of a peach orchard with high yield. Using biochemical and physiological analysis as well as phylogenetic sequencing data, we identified a strain of Bacillus methylotrophicus, strain XJ-C. The results of our screening trials showed that XJ-C was able to suppress M. fructicola at an inhibition rate of 81.57%. Following the application of a 1×109 CFU/mL XJ-C strain suspension to the fruits, leaves, and shoots of peach trees infected with M. fructicola, the inhibition rate reached 64.31%, 97.34%, and 64.28%, respectively. Using OM and SEM, we observed that, under the inhibition of strain XJ-C, M. fructicola mycelium and spores were abnormally shaped. Under TEM, cell walls were transparent, organelles had disappeared, and the intracellular vacuole was deformed. Thus, XJ-C has the potential to be used in biocontrol.

Bioactive Hybrid Composite Membrane with Enhanced Antimicrobial Properties for Biomedical Applications

2016 ◽  
Vol 66 (4) ◽  
pp. 434 ◽  
Author(s):  
Abin Davis ◽  
Balasubramanian K.
Keyword(s):  
Antimicrobial Properties ◽  
Cost Effective ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Force Microscopy ◽  
Chitosan Matrix ◽  
Effective Manner ◽  
Potential Applications ◽  
Membrane Roughness

<p class="p1"> </p><p class="p2"><span class="s1"> </span><em>Azadirachta indica </em>extract has been explored as an antibiotic in hygienic chitosan matrix system to enhance antimicrobial and medicinal property in a cost effective manner. The hygienic composite system has been successfully fabricated via solvent casting. The antibacterial activities of the hybrid system were examined by agar diffusion method against gram positive <em>S.aureus </em>and gram negative <em>K. pneumoniae. </em>From conventional antibacterial test for 24 h, the system exhibited an excellent antimicrobial activity against both bacterial strains in ranges of 1.2 cm - 1.5 cm for <em>S. aureus </em>and 1.8 cm <em>- </em>2.3 cm for <em>K. pneumoniae </em>Fourier transform infrared spectroscopy revealed successfully embedded A. indica on the chitosan substrate via weak electrostatic interaction, resulting in the easy release of the additive. Moreover, atomic force microscopy showed a membrane roughness of 0.084 nm which confirms the uniform distribution of the additive throughout the membrane. These hybrid membranes have potential applications in skin tissue engineering, wound healing and as coatings for implantable scaffold material.</p>

Powder, Paper and Foam of Few-Layer Graphene Prepared in High Yield by Electrochemical Intercalation Exfoliation of Expanded Graphite

Small ◽  
2013 ◽  
Vol 10 (7) ◽  
pp. 1421-1429 ◽  
Author(s):  
Liqiong Wu ◽  
Weiwei Li ◽  
Peng Li ◽  
Shutian Liao ◽  
Shengqiang Qiu ◽  
...  
Keyword(s):  
Expanded Graphite ◽  
High Yield ◽  
Layer Graphene ◽  
Electrochemical Intercalation ◽  
Few Layer Graphene

scholarly journals Biotechnological Production of the Sunscreen Pigment Scytonemin in Cyanobacteria: Progress and Strategy

Marine Drugs ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 129
Author(s):  
Xiang Gao ◽  
Xin Jing ◽  
Xufeng Liu ◽  
Peter Lindblad
Keyword(s):  
High Efficiency ◽  
Cost Effective ◽  
Gene Clusters ◽  
Central Carbon Metabolism ◽  
Biochemical Properties ◽  
High Yield ◽  
Nostoc Punctiforme ◽  
Biosynthetic Gene Clusters ◽  
Acid Biosynthesis ◽  
Biotechnological Production

Scytonemin is a promising UV-screen and antioxidant small molecule with commercial value in cosmetics and medicine. It is solely biosynthesized in some cyanobacteria. Recently, its biosynthesis mechanism has been elucidated in the model cyanobacterium Nostoc punctiforme PCC 73102. The direct precursors for scytonemin biosynthesis are tryptophan and p-hydroxyphenylpyruvate, which are generated through the shikimate and aromatic amino acid biosynthesis pathway. More upstream substrates are the central carbon metabolism intermediates phosphoenolpyruvate and erythrose-4-phosphate. Thus, it is a long route to synthesize scytonemin from the fixed atmospheric CO2 in cyanobacteria. Metabolic engineering has risen as an important biotechnological means for achieving sustainable high-efficiency and high-yield target metabolites. In this review, we summarized the biochemical properties of this molecule, its biosynthetic gene clusters and transcriptional regulations, the associated carbon flux-driving progresses, and the host selection and biosynthetic strategies, with the aim to expand our understanding on engineering suitable cyanobacteria for cost-effective production of scytonemin in future practices.

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