scholarly journals The effect of the synthesis conditions on structure and photocatalytic activity of Nb2O5 nanostructures

2018 ◽  
Vol 12 (3) ◽  
pp. 218-229 ◽  
Author(s):  
Caterine Gómez ◽  
Jorge Rodríguez-Páez
Keyword(s):  
Acetic Acid ◽  
Niobium Pentoxide ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Photo Degradation ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Heat Treated ◽  
Solid Precipitate ◽  
Controlled Precipitation

In this work, niobium pentoxide (Nb2O5) nanoparticles of varying sizes and morphology were synthesized using the controlled precipitation method. Ammonium niobate oxylate hydrate (NH4)H2[NbO(C2O4)3] ? 3H2O was used as a niobium precursor and distilled water or acetic acid was used as solvent. The obtained solids were characterized using Fourier transform infrared and Raman spectroscopies, X-ray diffraction and transmission electron microscopy. The as-synthesized solid precipitate was amorphous, but after heat treatment between 500?C and 600?C, the T-Nb2O5 phase was obtained. The size of the primary particles of the niobium pentoxide was nanometric (<100 nm), with agglomerate size of >500 nm, when water was used as a solvent for synthesis. Considering the nature of the process, a possible reaction mechanism of the precursor with the water and NH4OH was proposed, which explains the formation of the solid within an aqueous solution. Considering one potential use of Nb2O5 synthesized in this work, the photo-degradation action of the particles on the organic molecule methylene blue was tested. The sample synthesized in acetic acid at pH ~9.0 and heat treated at 600?C showed the highest photo-degradation capacity, with a degradation of ~60% of the dye for 60 minutes.

Synthesis Conditions of Nano-Hydroxyapatite Using Chondroitin Sulfate by Co-Precipitation Method

2011 ◽  
Vol 236-238 ◽  
pp. 2076-2079
Author(s):  
Yan Rong Sun ◽  
Tao Fan ◽  
Yong Huang ◽  
Li Guo Ma ◽  
Feng Liu
Keyword(s):  
Chondroitin Sulfate ◽  
Ph Value ◽  
Orthogonal Design ◽  
Precipitation Method ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Co Precipitation

The introduction of biomineralization was coupled with the co-precipitation synthesis process of nano-hydroxyapatite with the addition of chondroitin sulfate as a template agent. The effect of a variety of processing conditions on the properties of final hydroxyapatite (HA) product was investigated by orthogonal design. The ratio of calcium to phosphorus was detected by chemical analysis, the phase composition was evaluated by X-ray diffraction (XRD), and the powder morphology was characterized by transmission electron microscope (TEM). The process scheme, moreover, was optimized by the analysis of four aspects which may have different extent of influence on product properties. It can be concluded from the results that product properties can be affected remarkably by the content of chondroitin sulfate and the pH value of reactant, less remarkably by the reaction temperature and slightly by the reaction time.

A TEM investigation of a hyper-eutectic lead-tin alloy

1988 ◽  
Vol 46 ◽  
pp. 562-563
Author(s):  
John A. Sutliff
Keyword(s):  
Volume Diffusion ◽  
Eutectic Mixture ◽  
Precipitation Reaction ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffusion Controlled ◽  
Discontinuous Precipitation Reaction ◽  
Controlled Precipitation

Near-eutectic Pb-Sn alloys are important solders used by the electronics industry. In these solders, the eutectic mixture, which solidifies last, is the important microstructural consituent. The orientation relation (OR) between the eutectic phases has previously been determined for directionally solidified (DS) eutectic alloys using x-ray diffraction or electron chanelling techniques. In the present investigation the microstructure of a conventionally cast, hyper-eutectic Pb-Sn alloy was examined by transmission electron microscopy (TEM) and the OR between the eutectic phases was determined by electron diffraction. Precipitates of Sn in Pb were also observed and the OR determined. The same OR was found in both the eutectic and precipitation reacted materials. While the precipitation of Sn in Pb was previously shown to occur by a discontinuous precipitation reaction,3 the present work confirms a recent finding that volume diffusion controlled precipitation can also occur.Samples that are representative of the solder's cast microstructure are difficult to prepare for TEM because the alloy is multiphase and the phases are soft.

Magnetic and dielectric properties of BiFeO3 nanoparticles

2015 ◽  
Vol 7 (2) ◽  
pp. 1393-1403
Author(s):  
Dr R.P VIJAYALAKSHMI ◽  
N. Manjula ◽  
S. Ramu ◽  
Amaranatha Reddy
Keyword(s):  
Diffuse Reflectance Spectrum ◽  
Precipitation Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Bifeo3 Nanoparticles ◽  
Transmission Electron ◽  
Multiferroic Bifeo3 ◽  
Pure Phase ◽  
Simple Chemical ◽  
Co Precipitation

Single crystalline nano-sized multiferroic BiFeO3 (BFO) powders were synthesized through simple chemical co-precipitation method using polyethylene glycol (PEG) as capping agent. We obtained pure phase BiFeO3 powder by controlling pHand calcination temperature. From X-ray diffraction studies the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure belonging to the space group of R3c. No secondary phases were detected. It indicates single phase structure. EDX spectra indicated the appearance of three elements Bi, Fe, O in 1:1:3. From the UV-Vis diffuse reflectance spectrum, the absorption cut-off wavelength of the BFO sample is around 558nm corresponding to the energy band gap of 2.2 eV. The size (60-70 nm) and morphology of the nanoparticles have been analyzed using transmission electron microscopy (TEM).   Linear M−H behaviour and slight hysteresis at lower magnetic field is observed for BiFeO3 nanoparticles from Vibrating sample magnetometer studies. It indicates weak ferromagnetic behaviour at room temperature. From dielectric studies, the conductivity value is calculated from the relation s = L/RbA Sm-1 and it is around 7.2 x 10-9 S/m.

scholarly journals Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Visible Region ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

Template Induced Synthesis of Nano-Hydroxyapatite by Co-Precipitation Method

2011 ◽  
Vol 311-313 ◽  
pp. 1713-1716 ◽  
Author(s):  
Yan Rong Sun ◽  
Tao Fan ◽  
Chang An Wang ◽  
Li Guo Ma ◽  
Feng Liu
Keyword(s):  
Electron Microscope ◽  
Chondroitin Sulfate ◽  
Aspartic Acid ◽  
Transmission Electron Microscope ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Transmission Electron ◽  
Co Precipitation

Nano-hydroxyapatite with different morphology was synthesized by the co-precipitation method coupled with biomineralization using Ca(NO3)2•4H2O and (NH4)2HPO4 as reagents, adding chondroitin sulfate, agarose and aspartic acid as template. The structure and morphology of the prepared powders were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM).

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

scholarly journals Magnetic PbFe12O19-TiO2 nanocomposites and their photocatalytic performance in the removal of toxic pollutants

2018 ◽  
Vol 41 (3-4) ◽  
pp. 53-62 ◽  
Author(s):  
Behnaz Lahijani ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Photocatalytic Effect ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation

Abstract In this work, the PbFe12O19 nanoparticles were prepared by the simple and optimized precipitation method with different organic surfactants and capping agents. In the next step, the TiO2 nanoparticles were synthesized using the sol-gel method. At the final step, the PbFe12O19-TiO2 nanocomposites were prepared via the sol-gel method. The effect of the precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results obtained by the vibrating sample magnetometer show the magnetic properties of the ferrite nanostructures. The photocatalytic effect of the PbFe12O19-TiO2 nanocomposite on the elimination of the azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation was evaluated. The results indicate that the prepared nanocomposites have acceptable magnetic and photocatalytic performance.

scholarly journals Fabrication of a Food Nano-Platform Sensor for Determination of Vanillin in Food Samples

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2817 ◽  
Author(s):  
Vinod Gupta ◽  
Hassan Karimi-Maleh ◽  
Shilpi Agarwal ◽  
Fatemeh Karimi ◽  
Majede Bijad ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Food Samples ◽  
Precipitation Method ◽  
Single Wall Carbon Nanotubes ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Paste Electrode

Herein, we describe the fabrication of NiO decorated single wall carbon nanotubes (NiO-SWCNTs) nanocomposites using the precipitation method. The synthesized NiO-SWCNTs nanocomposites were characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Remarkably, NiO-SWCNTs and 1-butylpyridinium hexafluorophosphate modified carbon paste electrode (CPE/NiO-SWCNTs/BPrPF6) were employed for the electrochemical detection of vanillin. The vanillin sensor showed an ultra-high sensitivity of 0.3594 μA/μM and a low detection limit of 0.007 μM. In the final step, the NiO-SWCNTs/BPrPF6 was used as the suitable tool for food analysis.

scholarly journals PREPARATION OF NICKEL NANOWIRES AND EFFECTS OF SYNTHESIS CONDITIONS ON THEIR MORPHOLOGY

2019 ◽  
Vol 57 (3A) ◽  
pp. 21
Author(s):  
Minh Truong Xuan Nguyen ◽  
Thu Thi Minh Bui ◽  
Cuc Thi Le ◽  
Linh Huu Nguyen ◽  
Y Ngoc Pham ◽  
...  
Keyword(s):  
Synthesis Process ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Synthesis Conditions ◽  
Nickel Nanowires ◽  
Transmission Electron ◽  
Experimental Parameters ◽  
Polyol Medium ◽  
Nickel Nanostructures

Nickel nanostructures prepared by various methods have received considerable attentions due to their numerous applications. In this study, one-dimensional nickel nanowires (NiNWs) were synthesized by the reduction of nickel (II) chloride in polyol medium. Poly (vinylpyrrolidone) (PVP) served as the surfactant and hydrazine hydrate was used as the reductant. The effects of different experimental parameters, i.e. concentration of Ni2+, volume of N2H4, concentration of PVP and reaction temperature on the formation and morphology of NiNWs were studied. The structure, composition and surface morphology of the materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the morphology as well as the diameter of NiNWs could be effectively controlled by adjusting parameters of the synthesis process.

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