Synthesis of CuO and Cu2O nano/microparticles from a single precursor: effect of temperature on CuO/Cu2O formation and morphology dependent nitroarene reduction

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 85083-85090 ◽  
Author(s):  
V. Vinod Kumar ◽  
A. Dharani ◽  
Mariappan Mariappan ◽  
Savarimuthu Philip Anthony
Keyword(s):  
Hydrothermal Method ◽  
Effect Of Temperature ◽  
Single Precursor ◽  
Nitroarene Reduction

CuO and Cu2O micro/nanoparticles have been synthesized from same precursor in hydrothermal method by controlling temperature and morphology dependent nitroarenes reduction was studied with CuO nano/microparticles.

Toluene Degradation by Thermal Catalytic Oxidation over K-OMS-2 Catalysts

2014 ◽  
Vol 931-932 ◽  
pp. 22-26
Author(s):  
Patiparn Boonruam ◽  
Sutasinee Neramittagapong ◽  
Arthit Neramittagapong ◽  
Kitirote Wantala
Keyword(s):  
Manganese Oxide ◽  
Hydrothermal Method ◽  
Space Velocity ◽  
Precipitation Method ◽  
Effect Of Temperature ◽  
Toluene Degradation ◽  
Toluene Removal ◽  
Surface Areas ◽  
Toluene Concentration ◽  
Xrd Patterns

The goal of this research was to synthesize two different catalysts, namely K-OMS-2 and MnOx. The K-OMS-2 was an octahedral manganese complex prepared by hydrothermal method, while manganese oxide (MnOx) was directly synthesized by precipitation method. Both catalysts were employed to decompose toluene, an organic solvent that is widely used in industries. The catalysts were characterized by means of X-ray diffraction (XRD) and N2-physorption. The surface areas of K-OMS-2 and MnOx were 83.50 and 20.04 m2/g, respectively. The precipitation route gave XRD patterns of γ-Mn2O3 structure, and a successful structure of an octahedral molecular sieve manganese oxide was obtained by the hydrothermal method. The toluene degradation was carried out in gas hourly space velocity (GHSV) range of 20,000-60,000 h-1 with toluene concentration of 7,700 ppmv. The higher GHSV over K-OMS-2 gave the lower contact time consequently resulting in the lower %toluene degradation, whereas the best GHSV over γ-Mn2O3 was suitable at 40,000 h-1. The complete oxidation temperature of toluene over K-OMS-2 occurred at 260 °C and was lower than the temperature by γ-Mn2O3 at 300 °C. The higher surface area of K-OMS-2 may not facilitate internal toluene diffusion to active K-OMS-2 sites because molecular toluene (5.6 Å) cannot migrate through its smaller pore diameter (4.6 Å); however, the fully oxidized K-OMS-2 can provide higher average oxidation state (AOS) and higher amount of lattice oxygen assisting toluene degradation compared to γ-Mn2O3. The full factorial design of experiment (DOE) exhibited a strong effect of temperature and catalyst types on toluene removal; in contrast gas hour space velocity (GHSV) exhibited no significant effect on %toluene removal even with increasing GHSV.

Low Temperature Synthesis of PbTiO3 Nanoparticles

2005 ◽  
Vol 475-479 ◽  
pp. 3517-3520
Author(s):  
Yu Jing Sun ◽  
Shi Tian ◽  
Xiao Bing Li
Keyword(s):  
Hydrothermal Synthesis ◽  
Low Temperature ◽  
Hydrothermal Method ◽  
Tetragonal Phase ◽  
Lead Acetate ◽  
Average Diameter ◽  
Effect Of Temperature ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis

PbTiO3 nano-sized powders were synthesized at 150oC by a new hydrothermal [denoted as sol-hydrothermal] method by using modified titanium tetra-n-butoxide and lead acetate as the precursors. Furthermore, tetragonal PbTi0.8O2.6 nano-sized powders were obtained by this method at 80oC. Compared with hydrothermal synthesis, the effect of temperature on the formation of products prepared by sol-hydrothermal was investigated. The characteristics of products were studied by XRD, TEM and SAXS. The results show sol-hydrothermal method choosing acetylacetonate-modified titanium tetra-n-butoxide and lead acetate to form a sol could obtain PbTiO3 in 120nm size and PbTi0.8O2.6 powders with average diameter of 30nm, and both of them are pure tetragonal phase. In addition, PbTi0.8O2.6 could be converted into PbTiO3 gradually after annealed at giving condition.

The effect of temperature on morphology and electrochemical properties of NiCo2S4 by hydrothermal synthesis

2018 ◽  
Vol 11 (03) ◽  
pp. 1850063
Author(s):  
Yanwei Sui ◽  
Haihua Hu ◽  
Yuanming Zhang ◽  
Bin Tang ◽  
Jiqiu Qi ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Current Density ◽  
Level Structure ◽  
Hydrothermal Process ◽  
Effect Of Temperature ◽  
Second Step ◽  
Carbon Sphere

The hydrothermal method, using the template is a conspicuous way to change the morphology of the product, so it is used widely in many reports. The effect of temperature on morphology of NiCo2S4 by hydrothermal synthesis and its electrochemical properties is distinct as high-performance electrode materials for supercapacitors. With the help of the template (carbon sphere), different morphologies of NiCo2S4 under 90[Formula: see text]C, 120[Formula: see text]C and 180[Formula: see text]C were obtained. They have different properties after electrochemical analysis. In order to build a hierarchical multi-level structure, two-step vulcanization was carried out at each temperature, resulting in the difference in the morphology and performance of the six sample of electrodes. The obtained NiCo2S4 electrodes exhibit 1000[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text] in the second-step of the hydrothermal process under 120[Formula: see text]C, which is superior to the microblocks NiCo2S4 electrode (90[Formula: see text]C, 888[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text]) and microparticles NiCo2S4 electrode (180[Formula: see text]C, 574[Formula: see text]F[Formula: see text]g[Formula: see text] at the same current density) in the second-step hydrothermal, which shows a high-rate capability (640[Formula: see text]F[Formula: see text]g[Formula: see text] at 20[Formula: see text]A[Formula: see text]g[Formula: see text]). The obtained nanoparticles NiCo2S4 under 180[Formula: see text]C in the first-step hydrothermal electrode had an excellent cycle retention rate (89.7%), although its specific capacitance was lower. At the same time, the specific capacitance of these sample electrodes obtained in the second-step hydrothermal process is superior to those from the first-step. It was mainly attributed to the fact that temperature can influence the morphology by controlling ion exchange. And our experiment aims to use the hydrothermal method and the template method to find a more suitable temperature range to provide more ideas.

Green synthesis and characterization of flower-like PbS and metal-doped nanostructures via hydrothermal method

2017 ◽  
Vol 40 (1-2) ◽  
Author(s):  
Mohsen Kord ◽  
Kambiz Hedayati ◽  
Marziyeh Farhadi
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Ultra Violet ◽  
Cost Effective ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Metal Doped ◽  
Acid Blue

AbstractIn this work, flower-like nanoparticles of lead sulfide (PbS) and metal-doped PbS nanostructures were synthesized via a simple hydrothermal method in water as a green solvent. The effect of temperature, precipitating agent and capping agent on the morphology and particle size of the products was investigated. Sugars were used as green, safe, cost-effective, and bio-compatible capping agents. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and ultra violet-visible spectroscopy. The effect of PbS as a photocatalyst on the degradation of three different azo dyes was investigated. Acid brown, acid violet, and acid blue were totally degraded at 60 min under ultra-violet irradiation.

Effect of Temperature and KOH Concentration on Hydrothermal Synthesis of SrTiO3 Dendrites

2012 ◽  
Vol 430-432 ◽  
pp. 225-228
Author(s):  
Lin Lin Yang ◽  
Yu Jiang Wang ◽  
Qi Qun Zou ◽  
Yong Gang Wang
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Effect Of Temperature ◽  
Morphology Evolution

SrTiO3dendrites were successfully synthesized by hydrothermal method. An obvious morphology evolution from cubic-like shape to dendrite was observed when KOH concentration varied from 1M to 0.1M at 80°C. A decrease in KOH concentration was found to be favorable for the formation of dendrites. Star-like shape SrTiO3crystals instead of dendrites were obtained when the temperature was lowed to 40°C.

Effect of Temperature on Structural and Optical Properties of ZnO Nanorods by Hydrothermal Method

2013 ◽  
Vol 591 ◽  
pp. 293-296 ◽  
Author(s):  
Xiao Yan Fei ◽  
Jun Luo ◽  
Shu Wang Duo ◽  
Hao Zhang ◽  
Xiang Min Xu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Hydrothermal Method ◽  
Zno Nanorods ◽  
Hexagonal Structure ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Sem Images ◽  
Zno Crystal ◽  
Ir Study

The ZnO nanorods were prepared at 130 °C, 160 °C and 190 °C for 6 h by hydrothermal method. The structural and optical properties of ZnO nanorods were invesitigated by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). XRD pattern analysis showed that the ZnO nanorods are the hexagonal structure (space group P63 mc). No other crystal phases, such as Zn and Zn (OH)2 were detected. FT-IR study identified the sharp peak that appeared at 573 cm-1 is related with the ZnO stretching mode. Also, SEM images revealed that the diameter of a single ZnO crystal ranges from 100 to 300 nm and the length ranges from 1 to 3 μm.

Study of the temperature effect on the morphology and structure of ZnS nanoparticles synthesized by hydrothermal method

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3379-3388
Author(s):  
Claudia J. Bahena-Martínez ◽  
Nayely Torres-Gómez ◽  
Alfredo R. Vilchis-Néstor
Keyword(s):  
Hydrothermal Synthesis ◽  
Temperature Effect ◽  
Hydrothermal Method ◽  
Formation Mechanism ◽  
Zinc Sulphide ◽  
Effect Of Temperature ◽  
Zns Nanoparticles ◽  
Temperature Increment ◽  
Morphology And Structure ◽  
Subsequent Decomposition

AbstractThe control over the materials structure is crucial for the modulation of its properties, in order to achieve this control is important to know the formation mechanism of the material as function of parameters used. For this purpose, the effect of temperature (120, 140, 160 and 180 °C) on the hydrothermal synthesis of zinc sulphide is evaluated and a proposal of the sequence of reactions formation of zinc sulphur is presented. ZnS nanostructures with blend-phase were obtained, the temperature increment induces the growth of the nanostructure ranged between .62 and 12.72 nm, furthermore, increase the crystallinity of the ZnS nanostructures. The proposed reactions suggest the formation of a complex of thioacetamide with the Zn+2 and its subsequent decomposition into ZnS.

scholarly journals Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 843
Author(s):  
Zhongqi Wei ◽  
Qin Zhang ◽  
Xianbo Li
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Hydrothermal Method ◽  
Crystallization Kinetics ◽  
Calcium Sulfate ◽  
Control Process ◽  
Effect Of Temperature ◽  
Model Calculations ◽  
Crystallization Curve ◽  
Kinetics Of

α-Calcium sulfate hemihydrate (α-HH) is an important cementitious material, which can be prepared by hydrothermal method from calcium sulfate dihydrate (DH) in an electrolyte solution. Study of the conversion kinetics of DH to α-HH in NaCl solution is helpful for understanding the control process. In this paper, X-ray diffraction (XRD) patterns were applied to study the effect of temperature on the crystallization kinetics of α-HH to determine the kinetic parameters. The research results show that the sigmoidal shape of the α-HH crystallization curve follows the Avrami-Erofeev model, which describes the crystallization kinetics of α-HH formation. Applying Arrhenius law in experimental data and model calculations, an apparent activation energy of 124 kJ/mol for nucleation and an apparent activation energy of 810 kJ/mol for growth were obtained. By adjusting the temperature of the solution, the number of α-HH nucleation and growth steps increases, which can effectively increase the DH-α-HH conversion rate in the NaCI solution.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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