Preparation and Characterization of Mg Doped ZnAI2O4Spinel Nanoparticles

2021 ◽  
Vol 21 (11) ◽  
pp. 5659-5665
Author(s):  
P. Sakthivel ◽  
R. Jothi Ramalingam ◽  
D. Pradeepa ◽  
S. Rathika ◽  
Chandra Sekhar Dash ◽  
...  
Keyword(s):  
Band Gap ◽  
Data Storage ◽  
Diffuse Reflectance Spectroscopy ◽  
Magnetic Measurements ◽  
Average Crystallite Size ◽  
Fuel Component ◽  
X Ray ◽  
Uniform Distributions ◽  
Ion Doping ◽  
The Impact

In the present study, combustion technique is adopted to study the impact of Mg2+ ion doping on ZnAI2O4 nanoparticles (NPs). L-arginine is used as a fuel component. The Mg2+ ions play a pivotal role in persuading various characteristics of ZnAI2O4 NPs. Various characterization technqiues such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), Thermo-gravimetric/differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM) were carried out in order to synthesize the nanoparticles. Single phase cubic spinel structure of ZnAl2O4 (gahnite) formation was confirmed from the XRD characterization process of the nanoparticles. Estimated average crystallite size range of 11.85 nm to 19.02 nm was observed from Debye-Scherrer. Spherical morphology with uniform distributions was observed from HR-SEM characterization images. From the band gap studies, the attained band gap values were found to lie within 5.41 eV–4.66 eV range. The ZnAl2O4 and Mg:ZnAl2O4 NPs exhibited super-paramagnetic nature confirmed by magnetic measurements. The obtained results make ZnAl2O 4and Mg:ZnAl2O4 NPs appropriate for various optical, catalytic, energy and data storage applications.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

scholarly journals Impact of Preparative pH on the Morphology and Photocatalytic Activity of BiVO4

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Yongbiao Wan ◽  
Sihong Wang ◽  
Wenhao Luo ◽  
Lianhua Zhao
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Ammonia Solution ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Blue Solution ◽  
Absorption Performance ◽  
The Impact

Adjusting pH with an ammonia solution during the synthesis, single-crystalline BiVO4has been prepared using Bi(NO3)3·5H2O and NH4VO3as starting materials through aqueous-phase precipitation at room temperature. The prepared samples are characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). The impact of pH on structure, surface morphology, visible-light photocatalytic activity, and light absorption performance of BiVO4is explored and discussed. During the synthesis process, neither extremely acidic (low pH) nor basic (high pH) conditions are desirable for the formation of BiVO4in monoclinic phase. The highest photocatalytic performance on the degradation of a methylene blue solution is observed under pH=7.0for BiVO4in monoclinic scheelite, which is attributed to its small grain size and marked surface oxygen evolution ability.

Study on Band Gap Energy of F Doped TiO2 Nanotubes

2017 ◽  
Vol 889 ◽  
pp. 234-238
Author(s):  
Mohd Hasmizam Razali ◽  
Nur Arifah Ismail ◽  
Mahani Yusoff
Keyword(s):  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Small Diameter ◽  
Ultra Violet ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gap Energy ◽  
Transmission Electron ◽  
Xrd Patterns

Pure and F doped TiO2 nanotubes was synthesized using simple hydrothermal method. The hydrothermal was conducted using teflon-liner autoclave and maintained at 150oC for 24 hours. The characterization of synthesised product was carried out using x-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive of x-ray spectroscopy (EDX) and ultra violet – visible light diffuse reflectance spectroscopy (UV-Vis DRS) for band gap measurements. XRD patterns indicated that anatase TiO2 phase was remained after F doping suggested that fluorine was highly dispersed into TiO2 by substituted with O in the TiO2 lattice to formed TiO2-xFx solid solution. Morphology investigation using TEM found out small diameter of nanotubes structure within 8 – 10 nm of pure and F doped TiO2 nanotubes. The band gap energy (Eg) of both nanotubes samples were almost similar proposing that F doping does not modify the band gap energy.

A Microwave Route for the Synthesis of Nanoflakes and Dendrites-Type β-In2S3 and their Characterization

2006 ◽  
Vol 6 (3) ◽  
pp. 845-851 ◽  
Author(s):  
Chitta Ranjan Patra ◽  
Sujata Patra ◽  
Alexandra Gabashvili ◽  
Yitzhak Mastai ◽  
Yuri Koltypin ◽  
...  
Keyword(s):  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
High Yield ◽  
Nano Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Photo Acoustic Spectroscopy

In this article, a simple microwave route was applied for the synthesis of nanoflakes and dendrite-type β-indium sulfide (In2S3) in high yield (>97%), using a homogeneous mixture of indium(III)chloride and thiourea in an ethylene glycol (EG)/polyethylene glycol (PEG400) solvent. The reaction was conducted in a simple domestic microwave oven (DMO). Powder X-ray diffraction (XRD), low resolution and high resolution transmission electron microscopy (LRTEM and HRTEM), selected area electron diffraction (SAED), and energy dispersive X-ray spectroscopy (EDS), were applied to investigate the crystallinity, structure, morphology, and composition of the In2S3 nano-materials. Both the as-synthesized and calcined In2S3 products were a body-centered tetragonal (bct) phase, observed by XRD and HRTEM. The length and width of the resulting nanoflakes were in the range of 70–600 nm and 4–10 nm, respectively. The optical band gap of the powder was determined by diffuse reflectance spectroscopy (DRS) and was found to be 2.44 eV. The electronic properties of the products were studied by measuring the optical absorption spectra using photo-acoustic spectroscopy. The band gap calculated by this method was found to be 2.52 eV. A possible mechanism for the formation of nanoflakes/dendrites-type In2S3 was also discussed.

scholarly journals Unravelling the impact of Ta doping on the electronic and structural properties of titania: A combined theoretical and experimental approach

2021 ◽  
Author(s):  
Vignesh Kumaravel ◽  
Maria Barbara Maccioni ◽  
Snehamol Mathew ◽  
Steven Hinder ◽  
John Bartlett ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Structural Characteristics ◽  
Energy Levels ◽  
Average Crystallite Size ◽  
Defect States ◽  
X Ray ◽  
The Impact ◽  
Ta Doping

The introduction of new energy levels in the forbidden band through the doping of metal ions is an effective strategy to improve the thermal stability of TiO2. In the present study, the impact of Ta doping on the anatase to rutile transition (ART), structural characteristics, anion and cation vacancy formation were investigated in detail using Density Functional Theory (DFT) and experimental characterisation including, X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). The average crystallite size of TiO2 decreases with an increase in the Ta concentration. At high temperatures, more oxygen atoms entered the crystal lattice and occupy the vacancies, leading to lattice expansion. Importantly, we find that Ta doping preserved the anatase content of TiO2 up to annealing temperatures of 850 °C which allows anatase stability to be maintained at typical ceramic processing temperatures. The substitution of Ti4+ by the Ta5+ ions increased the electron concentration in the crystal lattice through formation of Ti3+ defect states. Raman studies revealed the formation of new Ta bonds via disturbing the Ti-O-Ti bonds in the crystal lattice. It is concluded that under the oxidising conditions, Ta5+ ions could be enhanced on Ta-TiO2 surface due to the slow diffusion kinetics.

scholarly journals Room Temperature Ferromagnetic and Optical Properties of Chrome Doped ZnS Nanorods Prepared by Hydrothermal Method

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Wenhua Zhao ◽  
Zhiqiang Wei ◽  
Li Zhang ◽  
Xiaojuan Wu ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Room Temperature ◽  
Single Phase ◽  
Diffuse Reflectance Spectroscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
Pl Spectra ◽  
Cr Concentration

Cr doped Zn1-xCrxS nanorods with different concentration ratio (x=0, 0.01, 0.03, and 0.05) were successfully synthesized by hydrothermal method. The crystal microstructure, morphology, chemical composition, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra, and the vibrating sample magnetometer (VSM). All the samples synthesized by this method exhibited single-phase wurtzite structure with good crystallization as demonstrated by XRD studies, which indicated that all Cr ions successfully substituted for the lattice site of Zn2+ and generated single-phase Zn1-xCrxS. DRS revealed the band gap of doped Zn1-xCrxS underwent blue shift compared to that of the bulk ZnS. PL spectra showed obvious ultraviolet emission peak at 375 nm and two blue emissions appear about 500 and 580 nm. The blue emissions intensity of doped samples improved with the increase of Cr concentration, comparing to pure ZnS. Magnetic measurements indicated that the undoped and doped ZnS nanorods exhibited well-defined ferromagnetic behavior at room temperature. The saturation magnetization weakened significantly with increasing Cr concentration comparing to pure ZnS and reached minimum for 3% Cr.

scholarly journals Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
P. Nyamukamba ◽  
L. Tichagwa ◽  
S. Mamphweli ◽  
L. Petrik
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Of

Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation.

MAGNETIC CLUSTERS DEVELOPMENT IN OXIDIZED CeNi5 POWDER

2011 ◽  
Vol 25 (01) ◽  
pp. 11-20
Author(s):  
LIDIA REDNIC ◽  
MARIN COLDEA ◽  
IOSIF GRIGORE DEAC ◽  
VASILE REDNIC ◽  
NICOLAE ALDEA ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Average Crystallite Size ◽  
Magnetic Clusters ◽  
Small Shift ◽  
Metallic Component ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Valence Bands

Synthesis, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and magnetic measurements at low temperature of Ni metallic clusters covered by NiO , Ce 2 O 3 and CeO 2, obtained from CeNi 5 powder oxidized in air at different temperatures up to 800°C, are reported. The average crystallite size of Ni core and the thickness of NiO oxide formed at the surface increase with temperature due to recrystallization processes, from 34 nm at 300°C to 77 nm at 800°C and from 9 nm to 19 nm, respectively. Ni metallic component was detected both in XPS valence bands and core levels spectra only after sputtering. The hysteresis loop presents a small shift towards negative magnetic fields which confirms the presence of ferromagnetic Ni /antiferromagnetic NiO interfaces.

Effect of Mineralizer (KNO3) on the Structural and Optical Properties of h-MoO3 Nanocrystals

2012 ◽  
Vol 585 ◽  
pp. 110-114
Author(s):  
A. Chithambararaj ◽  
Arumugam Chandra Bose
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Crystallite Size ◽  
Optical Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Hexagonal Phase ◽  
Thermo Gravimetric Analysis ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Gravimetric Analysis

Single phase hexagonal molybdenum oxide (h-MoO3) nanocrystals were successfully synthesized by solution based chemical precipitation method. The effect of mineralizer (KNO3 salt) on hexagonal phase, crystallite size, and surface morphologies of MoO3 was investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis. The XRD result indicates that the diffractograms exhibit characteristic hexagonal phase of MoO3. From the line broadening analysis, the average crystallite size was calculated and estimated. A less crystallite size of 34 nm was obtained in the presence of mineralizing agent KNO3 in comparison to without mineralizer (46 nm). The particle exhibits rod like morphology with perfect hexagonal cross-section and well faceted top and side surfaces. Further, the thermal and optical properties were studied by thermo gravimetric analysis (TGA) and diffuse reflectance spectroscopy (DRS) measurements. The weight loss due to decomposition of intercalated water and ammonia were observed. By TGA analysis, the mineralizer assisted sample shows higher phase stability with the phase transition temperature of 520 °C due to the incorporation of K+ in MoO3 structure. The optical band gap energy was calculated using Kubelka-Muck function and the values were found to be 3.11 eV and 2.97 eV for KNO3 assisted and non-assisted MoO3 samples respectively. The observed increase in optical band gap (Eg) for h-MoO3 synthesized in the presence of KNO3 was attributed to the size dependent optical properties.

Formation of ordered cobalt nanowire arrays in the mesoporous silica channels

2006 ◽  
Vol 78 (9) ◽  
pp. 1749-1757 ◽  
Author(s):  
Marina V. Chernysheva ◽  
Nina A. Sapoletova ◽  
Andrei A. Eliseev ◽  
Alexey V. Lukashin ◽  
Yuri D. Tretyakov ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Data Storage ◽  
Magnetic Measurements ◽  
Silica Matrix ◽  
Nanowire Arrays ◽  
Magnetic Nanowires ◽  
Adsorption Method ◽  
X Ray ◽  
Storage Devices ◽  
Novel Variant

Here we report the synthesis and investigation of cobalt nanowire arrays using mesoporous silica as a host material. In the present work, a novel variant of synthesis of ordered magnetic nanowires in the mesoporous silica matrix was suggested. The method is based on incorporation of a hydrophobic metal compound Co2(CO)8 into the hydrophobic part of the silica-surfactant composite. The amount of cobalt intercalated into the mesoporous matrix was measured by chemical analysis (~5 wt %). Additional thermal modification was performed in order to provide a crystallization process of the cobalt nanowires. The prepared nanocomposites were characterized by X-ray diffraction (XRD), small-angle X-ray spectroscopy (SAXS), transmission electron microscopy (TEM), nitrogen capillary adsorption method (BET and BJH), and magnetic measurements. The anisotropy parameters of nanowires were determined using temperature dependence of magnetic susceptibility. For cobalt-containing sample annealed at 300 °C (form factor of nanowire higher than 16), the coercive force at room temperature was found to be 42.2 kA/m at saturation magnetization of 0.5 A.m2/kg, which is nearly sufficient for modern information recording media. According to TEM studies, cobalt particles are uniform and well ordered in the silica matrix. Thus, the suggested method leads to one-dimensional anisotropic nanostructures, which could find an application in high-density data storage devices.

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