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.

Ga-Modified Nanostructured ZnO: Characterization and Application in Dye-Sensitized Solar Cells

2008 ◽  
Vol 591-593 ◽  
pp. 13-17
Author(s):  
Agnaldo S. Gonçalves ◽  
Ana Flavia Nogueira ◽  
Marian R. Davolos ◽  
Naruhiko Masaki ◽  
Shozo Yanagida ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Solar Cells ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dye Sensitized Solar Cells ◽  
Binding Energies ◽  
Precipitation Method ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

ZnO has received great attention in many applications due to its electronic and optical properties. We report on the preparation of ZnO and gallium-containing ZnO (ZnO:Ga) nanoparticles by the precipitation method. The nanoparticles have the wurtzite structure and a high crystallinity. Gallium ions are present as Ga3+, as evidenced by the binding energies through XPS. Porosity and surface area of the powder increased under increasing gallium level, explained by the smaller particle size of ZnO:Ga samples compared with ZnO. The estimated optical band gap of ZnO was 3.2 eV, comparable to ZnO:Ga.

scholarly journals Synthesis and Characterization of Pure and Rare-Earth Metal Gd Doped SnO2-CuO Nanoparticles by Co-Precipitation Method

2018 ◽  
Vol 4 (5) ◽  
pp. 478-482
Author(s):  
L. Prakash ◽  
C. Tirupathi
Keyword(s):  
Rare Earth ◽  
Band Gap ◽  
Crystallite Size ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Average Crystallite Size ◽  
Cuo Nanoparticles ◽  
Precipitation Method ◽  
Pure Sno2 ◽  
Co Precipitation

Pure and rare-earth metal Gd doped SnO2-CuO nanoparticles were successfully prepared from the starting materials SnCl2, CuCl2 and doping element gadolinium nitrate. Pure and Gd doped SnO2-CuO were synthesized by co-precipitation method. The samples were characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), UV-Vis, SEM, EDX and dielectric studies. The XRD analysis reveals that the rare-earth metal Gd dopants were substituted into rutile SnO2-CuO nanoparticles. Pure SnO2-CuO nanoparticles have an average crystallite size of 15 nm and rare-earth metal Gd doped SnO2-CuO nanoparticles have 18 nm. The average crystallite size of the sample increases when dopant was used and XRD peak intensity also increases when compared to pure SnO2-CuO nanoparticles. The optical absorption measurements exposed the nanometric size of the materials influences the energy band gap. Optical band gap was found to be 5.08 eV for pure SnO2-CuO nanoparticles and 5.14 eV for Gd doped SnO2-CuO nanoparticles. Surface morphology of pure and Gd doped SnO2-CuO nanoparticles annealed at 400 °C shows that most of the particles are rod shaped and hence it may have better sensitivity. Dielectric constant and dielectric loss decrease with increasing frequency at 100 °C and 200 °C. Doped samples show larger dielectric properties than pure SnO2-CuO nanoparticles.

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.

scholarly journals Effect of concentration of cadmium sulfate solution on structural, optical and electric properties of Cd1–x Zn x S thin films

2021 ◽  
Vol 42 (11) ◽  
pp. 112101
Author(s):  
Yuming Xue ◽  
Shipeng Zhang ◽  
Dianyou Song ◽  
Liming Zhang ◽  
Xinyu Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Film Growth ◽  
Structural Characteristics ◽  
Hexagonal Phase ◽  
Zinc Content ◽  
Sulfate Concentration ◽  
Cadmium Sulfate

Abstract Cd1– x Zn x S thin films were deposited by chemical bath deposition (CBD) on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film. The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity. The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase, decrease, and increase with the increase of cadmium sulfate concentration. XRD studies exhibit the crystal structure of the film is the hexagonal phase, and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M. Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E g can be expressed by the equation E g(x) = 0.59x 2 + 0.69x + 2.43. Increasing the zinc content can increase the optical band gap, and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration, however, all of them have good transmittance. At a concentration of 0.005 M, the thin film has good absorbance in the 300–800 nm range, 80% transmittance, and band gap value of 3.24 eV, which is suitable for use as a buffer layer for solar cells.

Investigations on Cu2+-substituted Ni–Zn ferrite nanoparticles

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650347
Author(s):  
Amarjeet ◽  
Vinod Kumar
Keyword(s):  
Spinel Phase ◽  
Thermo Gravimetric Analysis ◽  
Peak Position ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Zn Ferrite

[Formula: see text] ([Formula: see text] = 0.1, 0.3 and 0.5) nanoparticles were prepared by chemical co-precipitation method. The developed nanoparticles were characterized for structural properties by powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Peak position in the X-ray diffraction pattern confirmed the single spinel phase of the developed particles. Infrared (IR) spectroscopy in mid-IR range showed the presence of characteristic absorption bands corresponding to octahedral and tetrahedral bonds in the spinel structure of prepared samples. Thermo-gravimetric analysis (TGA) measurements showed a considerable weight loss in the developed samples above 700[Formula: see text]C. Frequency dependence of the electrical properties of the developed material pellets was studied in the frequency range of 1 kHz–5 MHz. Temperature dependence of the dielectric constant of [Formula: see text] was studied at different temperatures, i.e. at 425, 450 and 475 K, in the frequency range of 1 kHz–5 MHz. It was found that the electrical conductivity decreases with increasing Cu[Formula: see text] ion content while it increases with the increase in temperature.

Effect of the ratio ZnO: ZrO2 on the photocatalytic ability of phenol degradation in ZnO-ZrO2 nanocompsite materials

2021 ◽  
Vol 10 (3) ◽  
pp. xx-xx
Author(s):  
Thao Pham Thi Minh ◽  
Huong Do Thi ◽  
Hai Le Thi
Keyword(s):  
Photocatalytic Activity ◽  
Crystallite Size ◽  
Phenol Degradation ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Ultrasonic Vibrations ◽  
Phenol Content ◽  
Photocatalytic Ability ◽  
Photocatalytic Reactions

The ZnO-ZrO2 nanocompsite materials in the molar ratio (1:0; 1:1; 1:2; 2:1; 3:4; 4:3; 0:1) were prepared by a two-stage precipitation method with ultrasonic vibrations. The obtained ZnO-ZrO2 materials were characterized by XRD, SEM, UV-vis. XRD data identified phase of the ZnO and phase of ZrO2 in all obtained samples. The average crystallite size of the samples was between 18 to 30 nm. As UV-Vis spectra, the band gap of ZnO-ZrO2 composite (ZZ34R) is 3,06eV. The photocatalytic reactions confirmed that the nanocomposite sample showed higher photocatalytic activity than the pure oxides samples for the degradation phenol under 100W incandescent lamp. Among the prepared samples, the best sample for photocatalytic degration of phenol is the ZZ34R which the molar ratio ZnO:ZrO2 = 3:4 with 23% remaining phenol content after 300 minutes. The photodegradation phenol of sample with ultrasonic vibrations is higher than the sample without ultrasonic vibrations. This indicates that the materials are capable of treating phenol in wastewater.

The Role of Reduced Graphene Oxide Concentration as Ablated Material on Optical Properties of Graphene Quantum Dots

2019 ◽  
Vol 948 ◽  
pp. 267-273 ◽  
Author(s):  
Fiqhri Heda Murdaka ◽  
Ahmad Kusumaatmaja ◽  
Isnaeni ◽  
Iman Santoso
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Oxide ◽  
Band Gap ◽  
Reduced Graphene Oxide ◽  
Optical Band Gap ◽  
Graphene Quantum Dots ◽  
Absorption Peak ◽  
Oxygen Defect ◽  
Reduced Graphene

We report the synthesize of Graphene Quantum Dots (GQDs) using ablation method with reduced Graphene Oxide (rGO) solution as a starting material. We have varied the concentration of rGO as following: 0.5, 2, 5 mg/ml and then have ablated them using 800 nm Ti-Sapphire femtosecond laser to obtain GQDs. From the UV-Vis data, we observed that the more concentration of rGO is being ablated, the more secondary absorption peak at 255.1 nm appeared. This secondary absorption peak is a characteristic of n-π* bonding due to the presence of oxygen defect which occurs as a result of the interaction between the laser and the water in rGO solution. We conclude that the population of oxigen defect in GQDs is increasing, following the increase of rGO concentration and could alter the optical properties of GQD. On the other hand, using Tauc’s plot, we confirm that the increase of rGO concentration as the ablated material does not alter GQDs optical band gap. However, it will slightly reduce both, direct and indirect Oxygen defect related optical band gap.

The Influence of Calcination Temperature on Quantitative Phase of Hematite from Iron Stone Tanah Laut

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Co Precipitation

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.

Optical Properties of Silica Borotellurite Glass Doped with Manganese Oxide

2017 ◽  
Vol 268 ◽  
pp. 18-22 ◽  
Author(s):  
I. Zaitizila ◽  
Mohamed Kamari Halimah ◽  
Farah Diana Mohammad ◽  
Mohd Shah Nurisya
Keyword(s):  
Optical Properties ◽  
Manganese Oxide ◽  
Band Gap ◽  
Diffraction Pattern ◽  
Optical Band Gap ◽  
Urbach Energy ◽  
Molar Fraction ◽  
Chemical Formula ◽  
Melt Quenching ◽  
Amorphous Nature

Silica borotellurite glasses doped with manganese oxide with chemical formula {[(TeO2)0.7(B2O3)0.3­]0.8[SiO2]0.2}1-x{MnO2}x (where x = 0.0, 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction) were fabricated. Silica were extracted from the burning process of rice husk. Glass samples were prepared by using the melt-quenching technique. The FTIR spectra showed that the addition of MnO₂ contributed to the transformation of TeO4 to TeO3. The diffraction pattern of XRD showed a broad hump which indicates the amorphous nature of the samples. The result for both optical band gap and Urbach energy showed decreasing trend as the concentration of manganese increased.

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