scholarly journals The facile one-step hydrothermal method to prepare MnO2 nanoparticles: Structural and electrochemical properties

2021 ◽  
Vol 2145 (1) ◽  
pp. 012034
Author(s):  
K Tangphanit ◽  
N Boonraksa ◽  
S Maensiri ◽  
E Swatsitang ◽  
K Wongsaprom
Keyword(s):  
Hydrothermal Method ◽  
Current Density ◽  
Average Particle Size ◽  
Nitrogen Adsorption ◽  
Spherical Particles ◽  
Average Particle ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
One Step ◽  
A Current

Abstract MnO2 nanoparticles were successfully prepared via one-step hydrothermal method. The surface are properties of the MnO2 nanoparticles were determined by BET nitrogen adsorption-desorption measurement. The XRD analyses confirm the pure phase of γ-MnO2 and α-MnO2, having orthorhombic crystal structure (JCPDS file no.14-0644 and 44-0141). FE-SEM analysis reveals the combination of massively small spherical particles with average particle size 54.8 nm. The electrochemical results revealed that the MnO2 nanoparticles delivered the specific capacitance of 200.83 F/g at a current density of 1A/g. The cycle stability was usability 30% after 500 cycles at a current density of 5 A/g. The MnO2 nanoparticles reveal a energy density of 3.62 Wh/kg under a power density of 43.11 W/kg.

The fabrication of Co:ZnS/CoS2 heterostructure nanowires with a superior hydrogen evolution performance

2019 ◽  
Vol 3 (10) ◽  
pp. 2771-2778 ◽  
Author(s):  
Shancheng Yan ◽  
Ka Wang ◽  
Qingxia Wu ◽  
Fei Zhou ◽  
Zixia Lin ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Current Density ◽  
High Hydrogen ◽  
Tafel Slope ◽  
One Step ◽  
A Current

The ultrafine Co:ZnS/CoS2 heterostructure nanowires with high hydrogen evolution performance by one-step hydrothermal method. The overpotential required to reach a current density of 10 mAcm−2 was only 78 mV in 0.5 M H2SO4 solution, and the Tafel slope was 56 mV dec−1.

Construction of a hierarchical NiFe layered double hydroxide with a 3D mesoporous structure as an advanced electrocatalyst for water oxidation

2018 ◽  
Vol 5 (8) ◽  
pp. 1795-1799 ◽  
Author(s):  
Jiahao Yu ◽  
Fulin Yang ◽  
Gongzhen Cheng ◽  
Wei Luo
Keyword(s):  
Hydrothermal Method ◽  
Layered Double Hydroxide ◽  
Current Density ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Cost Effective ◽  
Mesoporous Structure ◽  
One Step ◽  
Double Hydroxide ◽  
A Current

A facile and cost-effective one-step hydrothermal method is used to synthesize NiFe LDH microclusters with a 3D hierarchically mesoporous architecture. This superior electrocatalyst can achieve a current density of 10 mA cm−2 with an ultralow overpotential of 211 mV toward the oxygen evolution reaction.

Sintering Temperature Effect on the Structural and Electrical Transport Properties of Nanophasic Nd0.7Sr0.3MnO3 Manganite

2013 ◽  
Vol 209 ◽  
pp. 216-219 ◽  
Author(s):  
Jayant A. Bhalodia ◽  
Savan R. Mankadia
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Electrical Transport ◽  
Sintering Temperature ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Average Particle ◽  
Electrical Transport Properties ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure

A systematic investigation of neodymium-based manganite, Nd0.7Sr0.3MnO3, was undertaken with a view to understand the influence of sintering temperature on various physical properties. The materials were prepared by the a soft chemical approach of co-precipitation method by sintering at four different temperatures starting from 700 to 1000 °C, with an interval of 100 °C. X-ray diffraction (XRD), transmission electron microscopy (TEM) and D. C. four-probe resistivity were employed to study the crystal structure, average particle size and electrical property respectively. Analysis of XRD patterns shows that all the samples exhibit single phase orthorhombic crystal structure. We followed William-son Hall approach to calculate the lattice stain (ε).These materials were found to exhibit different metal-insulator transition temperature (TMI) for the different sintering temperature. The value of TMIincreases, as the sintering temperature increases, whereas ε decreases. TEM results show that with the increment of sintering temperature, the particle size of the NSMO samples also increases, which plays a key role on electrical transport. To understand the conduction mechanism in metallic and insulating regions of resistivity, various theoretical models are discussed in this communication.

scholarly journals Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1097
Author(s):  
Luran Zhang ◽  
Xinchen Du ◽  
Hongjie Lu ◽  
Dandan Gao ◽  
Huan Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Annealing Temperature ◽  
Reduction Method ◽  
Solid Phase ◽  
Average Particle Size ◽  
Fept Nanoparticles ◽  
Average Particle ◽  
Phase Reduction ◽  
Different Temperatures ◽  
One Step

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

Microstructure Characterization of Ag Nanoparticles Prepared by Hydrothermal Method

2012 ◽  
Vol 476-478 ◽  
pp. 1138-1141
Author(s):  
Zhi Qiang Wei ◽  
Qiang Wei ◽  
Li Gang Liu ◽  
Hua Yang ◽  
Xiao Juan Wu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Hydrothermal Method ◽  
Ag Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Face Centered

Ag nanoparticles were successfully synthesized by hydrothermal method under the polyol system combined with traces of sodium chloride, Silver nitrate(AgNO3) and polyvinylpyrrolidone (PVP) acted as the silver source and dispersant respectively. The samples by this process were characterized via X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) to determine the chemical composition, particle size, crystal structure and morphology. The experiment results indicate that the crystal structure of the samples is face centered cubic (FCC) structure as same as the bulk materials, The specific surface area is 24 m2/g, the particle size distribution ranging from10 to 50 nm, with an average particle size about 26 nm obtained by TEM and confirmed by XRD and BET results.

Preparation and Characterization of Terpenoid-Encapsulated PLGA Microparticles and its Antibacterial Activity against Enterococcus faecalis

2019 ◽  
Vol 829 ◽  
pp. 263-269
Author(s):  
Denny Nurdin ◽  
Andri Hardiansyah ◽  
Elsy Rahimi Chaldun ◽  
Anti Khoerul Fikkriyah ◽  
Hendra Dian Adhita Dharsono ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Average Particle Size ◽  
Poly Vinyl Alcohol ◽  
Prolonged Release ◽  
Average Particle ◽  
Plga Microparticles ◽  
Assay Result ◽  
Result Show ◽  
One Step

Exploration of natural compound for the treatment of dental-related problems are gaining of interest for enhancing therapeutic efficacy of the drugs delivery system. In this study, we have prepared terpenoid, which have been isolated from Myrmecodia pendens Merr & Perry from Papua Island, Indonesia, to be encapsulated in Polylactic-co-glycolic acid (PLGA), as the most widely used biodegradable polymer for biomedical applications, through one step single-emulsion method followed by subsequent coating by poly (vinyl alcohol) (PVA). The resultant of terpenoid-loaded PLGA microparticles were characterized systematically through scanning electron microscope and Fourier-transform infrared spectroscopy. In vitro drug release test was evaluated through dialysis method. Antibacterial test was conducted against Enterococcus faecalis as a model for persistent bacteria that causes root canal infections. The results showed that terpenoid-loaded PLGA microparticles were developed in spherical morphology with an average particle size of around 1-2μm. Terpenoid released from PLGA compartment at pH 6.5 and temperature of 37°C through a controlled-release profile mechanism with enhanced prolonged release. The bacterial assay result showed that terpenoid-loaded PLGA microparticles could reduce Enterococcus faecalis, effectively. Eventually, these result show that terpenoid-loaded PLGA microparticles as unique natural product-based extract could be developed as a potential naturally-based drug for dental-related diseases applications.

Kinetics of synthesizing process for obtaining iron nanopowder by chemical-metallurgical method under isothermal conditions

2021 ◽  
pp. 72-77
Author(s):  
Tien Hiep Nguyen ◽  
◽  
Van Minh Nguyen ◽  
Keyword(s):  
Hydrogen Reduction ◽  
Average Particle Size ◽  
Chemical Deposition ◽  
Reduction Process ◽  
Nitrogen Adsorption ◽  
Specific Rate ◽  
Average Particle ◽  
Isothermal Conditions ◽  
Electron Microscopes ◽  
Kinetics Of

In this work the kinetics of synthesizing process of metallic iron nanopowder by hydrogen reduction from α-FeOOH hydroxide under isothermal conditions were studied. α-FeOOH nanopowder was prepared in advance by chemical deposition from aqueous solutions of iron nitrate Fe(NO3)3 (10 wt. %) and alkali NaOH (10 wt. %) at room temperature, pH = 11, under the condition of continuous stirring. The hydrogen reduction process of α-FeOOH nanopowder under isothermal conditions was carried out in a tube furnace in the temperature range from 390 to 470 °C. The study of the crystal structure and composition of the powders was performed by X-ray phase analysis. The specific surface area S of the samples was measured using BET method by low-temperature nitrogen adsorption. The average particle size D of powders was determined via the measured S value. The size characteristics and morphology of the particles were investigated by transmission and scanning electron microscopes. The calculation of the kinetic parameters of the hydrogen reduction process of α-FeOOH under isothermal conditions was carried out by the Gray-Weddington model and Arrhenius equation. It is shown that the rate constant of reduction at 470 °C is approximately 2.2 times higher than in the case at 390 °C. The effective activation energy of synthesizing process of iron nanopowder by hydrogen reduction from α-FeOOH was ~38 kJ/mol, which indicates a mixed reaction mode. In this case, the kinetics overall process is limited by both the kinetics of the chemical reaction and the kinetics of diffusion, respectively, an expedient way to accelerate the process by increasing the temperature or eliminate the diffusion layer of the reduction product by intensive mixing. It is show that Fe nanoparticles obtained by hydrogen reduction of its hydroxide at 410 °C, corresponding to the maximum specific rate of the reduction process, are mainly irregular in shape, evenly distributed, the size of which ranges from several dozens to 100 nm with an average value of 75 nm.

scholarly journals Preparation, Characterization, and In Vivo Pharmacokinetic Study of the Supercritical Fluid-Processed Liposomal Amphotericin B

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 589 ◽  
Author(s):  
Chang-baek Lim ◽  
Sharif Md Abuzar ◽  
Pankaj Ranjan Karn ◽  
Wonkyung Cho ◽  
Hee Jun Park ◽  
...  
Keyword(s):  
Particle Size ◽  
Amphotericin B ◽  
Supercritical Fluid ◽  
Liposomal Amphotericin ◽  
Average Particle Size ◽  
Spherical Particles ◽  
Liposomal Amphotericin B ◽  
Average Particle ◽  
In Vivo Pharmacokinetics

Here, we aimed to prepare and optimize liposomal amphotericin B (AmB) while using the supercritical fluid of carbon dioxide (SCF-CO2) method and investigate the characteristics and pharmacokinetics of the SCF-CO2-processed liposomal AmB. Liposomes containing phospholipids, ascorbic acid (vit C), and cholesterol were prepared by the SCF-CO2 method at an optimized pressure and temperature; conventional liposomes were also prepared using the thin film hydration method and then compared with the SCF-CO2-processed-liposomes. The optimized formulation was evaluated by in vitro hemolysis tests on rat erythrocytes and in vivo pharmacokinetics after intravenous administration to Sprague-Dawley rats and compared with a marketed AmB micellar formulation, Fungizone®, and a liposomal formulation, AmBisome®. The results of the characterization studies demonstrated that the SCF-CO2-processed-liposomes were spherical particles with an average particle size of 137 nm (after homogenization) and drug encapsulation efficiency (EE) was about 90%. After freeze-drying, mean particle size, EE, and zeta potential were not significantly changed. The stability study of the liposomes showed that liposomal AmB that was prepared by the SCF method was stable over time. In vivo pharmacokinetics revealed that the SCF-CO2-processed-liposomes were bioequivalent to AmBisome®; the hemolytic test depicted less hematotoxicity than Fungizone®. Therefore, this method could serve as a potential alternative for preparing liposomal AmB for industrial applications.

Synthesis and Characterization of Nanocrystalline Anatase by Microwave Hydrothermal Method

2012 ◽  
Vol 500 ◽  
pp. 104-107
Author(s):  
Zhi Qin Chen ◽  
Xiang Liang Chen ◽  
Shu Juan Zhang ◽  
Jun Xi Hu ◽  
Wen Kui Li
Keyword(s):  
Hydrothermal Method ◽  
Average Particle Size ◽  
Butyl Alcohol ◽  
Molar Ratio ◽  
Tetrabutyl Titanate ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Microwave Hydrothermal ◽  
Microwave Hydrothermal Method

Uniform nanocrystalline pure anatase has been synthesized and characterized using tetrabutyl titanate aqueous solution as starting precursors by microwave hydrothermal method. The influences of synthesis conditions (reaction time and temperature) on the formation, crystal phase and crystallite size of TiO2has been investigated. A mixture solution of tetrabutyl titanate and normal butyl alcohol in 1:4 molar ratio is processed in a microwave hydrothermal autoclave at low temperature 120°C for different durations, at 200°C for 20 min to precipitate titania powders, respectively. It was revealed that uniformly dispersed and granulous single phase anatase prepared at 120°C for 180 min with the average particle size of 10 nm was formed by means of XRD and TEM.

Effect of Surfactant on the Preparation of Nano-powder for Yb Doping Laser Transparent YAG Ceramic

2013 ◽  
Vol 32 (5) ◽  
pp. 511-515 ◽  
Author(s):  
Xiao Guo Cao ◽  
Jia Wang ◽  
Qi Bai Wu ◽  
Hai Yan Zhang
Keyword(s):  
Particle Size ◽  
Polyethylene Glycol ◽  
Average Particle Size ◽  
Ammonium Bicarbonate ◽  
Spherical Particles ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Powder ◽  
Co Precipitation

AbstractYb:YAG transparent ceramic nano-powder was prepared by chemical co-precipitation method, with ammonium bicarbonate as the precipitant and polyethylene glycol as surfactant. The addition of polyethylene glycol can reduce the agglomeration and particle size of the prepared Yb:YAG powder. The morphology, thermal stability and phase structure of Yb:YAG nano-powder were charactered by scanning electron microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. The results show that well-crystallized nano-powder was obtained by calcining the precursors at 900 °C for 3 h. The average particle size of Yb:YAG powder is about 100–200 nm. When the volume amount of polyethylene glycol is 2.0%, well-dispersed Yb:YAG powder with spherical particles of 100 nm diameter was obtained.

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