scholarly journals Effect of substrate placement in schott vial to hematite properties

2019 ◽  
Vol 8 (1) ◽  
pp. 58-64
Author(s):  
Wan Rosmaria Wan Ahmad ◽  
M. H. Mamat ◽  
A. S. Zoolfakar ◽  
Z. Khusaimi ◽  
A. S. Ismail ◽  
...  
Keyword(s):  
Glass Substrate ◽  
Lattice Structure ◽  
Synthesis Method ◽  
Average Diameter ◽  
Band Gap Energy ◽  
Bandgap Energy ◽  
Xrd Pattern ◽  
Optical Bandgap Energy ◽  
Diffraction Peaks ◽  
Surface Morphologies

In the present study, hematite (α-Fe2O3) nanostructures were deposited on fluorine doped tin oxide (FTO) coated glass substrate using sonicated immersion synthesis method. The effect of FTO glass substrate placement in Schott vial during immersion process was studied on the growth of the hematite nanostructure and its properties. XRD pattern has revealed seven diffraction peaks of α-Fe2O3 for both hematite nanostructures samples attributed to polycrystalline with rhombohedral lattice structure. The surface morphologies from FESEM have shown that the hematite nanostructures were grown uniformly in both samples with FTO conductive layer facing up and down. Hematite sample with FTO facing down exhibits a smaller size of nanorod, 26.7 nm average diameter, compared to the hematite sample that FTO face up with 53.8nm average diameter. Optical properties revealed higher transmittance in the sample with FTO facing down, probably due to smaller size of nanostructure. The optical band gap energy plotted and extrapolated at 2.50eV and 2.55eV for FTO face up and FTO face down hematite samples respectively, presenting the sample with FTO face up has a lower optical bandgap energy.

scholarly journals Intrinsic ZnO/Al-doped ZnO Homojunction: Structural and Optical Properties

2018 ◽  
Vol 12 (1) ◽  
pp. 393
Author(s):  
A.S. Ismail ◽  
M.H. Mamat ◽  
M.F. Malek ◽  
M.M. Yusoff ◽  
N.D. Md. Sin ◽  
...  
Keyword(s):  
Optical Properties ◽  
Average Diameter ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Xrd Pattern ◽  
Good Crystallinity ◽  
Good Potential ◽  
Image Displays ◽  
Doped Zno

<p>Intrinsic zinc oxide (ZnO)/Al-doped ZnO (AZO) homojunction film was prepared using two-step immersion processes. The film was characterized using field emission scanning electron microscopy, X-ray diffraction (XRD), Raman spectroscopy, and ultraviolet–visible spectrophotometer to investigate their structural and optical properties. The surface morphology image displays that the ZnO deposited on the nanorod surfaces in layer form with average diameter of nanorods about 95 nm. The structural properties of XRD pattern demonstrate that the film possessed good crystallinity with the preferred orientation at (002) plane. The film also possessed excellent absorption in the ultraviolet (UV) region with optical band gap energy of 3.22 eV. These results indicate that the film has a good potential for optical-based device such a UV sensor.</p>

scholarly journals Preparation of Nanoparticle Porous-Structured BiVO4 Photoanodes by a New Two-Step Electrochemical Deposition Method for Water Splitting

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 136
Author(s):  
SocMan Ho-Kimura ◽  
Wasusate Soontornchaiyakul ◽  
Yuichi Yamaguchi ◽  
Akihiko Kudo
Keyword(s):  
Water Splitting ◽  
Electrochemical Deposition ◽  
Synthesis Method ◽  
Stoichiometric Ratio ◽  
Deposition Method ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Xrd Pattern ◽  
Conversion Reaction ◽  
Electrochemical Deposition Method

In the synthesis method of a BiVO4 photoanode via BiOI flakes, a BiOI film is formed by electrochemical deposition in Step 1, and a vanadium (V) source solution is placed by drop-casting on the BiOI film in Step 2. Following this, BiVO4 particles are converted from the BiOI–(V species) precursors by annealing. However, it is challenging to evenly distribute vanadium species among the BiOI flakes. As a result, the conversion reaction to form BiVO4 does not proceed simultaneously and uniformly. To address this limitation, in Step 2, we developed a new electrochemical deposition method that allowed the even distribution of V2O5 among Bi–O–I flakes to enhance the conversion reaction uniformly. Furthermore, when lactic acid was added to the electrodeposition bath solution, BiVO4 crystals with an increased (040) peak intensity of the X-ray diffractometer (XRD) pattern were obtained. The photocurrent of the BiVO4 photoanode was 2.2 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE) under solar simulated light of 100 mW/cm2 illumination. The Faradaic efficiency of oxygen evolution was close to 100%. In addition, overall water splitting was performed using a Ru/SrTiO3:Rh–BiVO4 photocatalyst sheet prepared by the BiVO4 synthesis method. The corresponding hydrogen and oxygen were produced in a 2:1 stoichiometric ratio under visible light irradiation.

scholarly journals Non-Isothermal Decomposition as Efficient and Simple Synthesis Method of NiO/C Nanoparticles for Asymmetric Supercapacitors

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 187
Author(s):  
Daria Chernysheva ◽  
Ludmila Pudova ◽  
Yuri Popov ◽  
Nina Smirnova ◽  
Olga Maslova ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Synthesis Method ◽  
Average Diameter ◽  
Carbon Support ◽  
Spherical Particles ◽  
Support Surface ◽  
Isothermal Decomposition ◽  
Step Method ◽  
Nickel Oxide Nanoparticles ◽  
Electrode Cell

A series of NiO/C nanocomposites with NiO concentrations ranging from 10 to 90 wt% was synthesized using a simple and efficient two-step method based on non-isothermal decomposition of Nickel(II) bis(acetylacetonate). X-ray diffraction (XRD) measurements of these NiO/C nanocomposites demonstrate the presence of β-NiO. NiO/C nanocomposites are composed of spherical particles distributed over the carbon support surface. The average diameter of nickel oxide spheres increases with the NiO content and are estimated as 36, 50 and 205 nm for nanocomposites with 10, 50 and 80 wt% NiO concentrations, respectively. In turn, each NiO sphere contains several nickel oxide nanoparticles, whose average sizes are 7–8 nm. According to the tests performed using a three-electrode cell, specific capacitance (SC) of NiO/C nanocomposites increases from 200 to 400 F/g as the NiO content achieves a maximum of 60 wt% concentration, after which the SC decreases. The study of the NiO/C composite showing the highest SC in three- and two-electrode cells reveals that its SC remains almost unchanged while increasing the current density, and the sample demonstrates excellent cycling stability properties. Finally, NiO/C (60% NiO) composites are shown to be promising materials for charging quartz clocks with a power rating of 1.5 V (30 min).

Thickness Dependent Structural and Optical Properties of Cadmium Selenide Thin Films

2013 ◽  
Vol 665 ◽  
pp. 159-167
Author(s):  
M.S. Jani ◽  
H.S. Patel ◽  
J.R. Rathod ◽  
K.D. Patel ◽  
V.M. Pathak ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Hexagonal Wurtzite Structure ◽  
Optical Bandgap ◽  
Bandgap Energy ◽  
Structural And Optical Properties ◽  
Structural Investigations ◽  
Glass Substrates ◽  
Optical Bandgap Energy ◽  
Different Thickness

In this paper structural and optical properties of CdSe thin films with different thickness deposited by thermal evaporation under vacuum onto glass substrates are presented. The structural investigations performed by means of XRD technique showed that the films have a polycrystalline and hexagonal (würtzite) structure. The values of some important parameters of the studied films (absorption coefficient and optical bandgap energy) are determined from transmission spectra. The values of the optical bandgap energy (Eg) calculated from the absorption spectra, ranged between 1.67 - 1.74 eV.

The Optical Performance of Holmium Oxide Doped Tellurite Glass for Potential Optical Fiber

2021 ◽  
Vol 317 ◽  
pp. 95-99
Author(s):  
Muhammad Noorazlan Abd Azis ◽  
Halimah Mohamed Kamari ◽  
Suriani Abu Bakar ◽  
Azlina Yahya ◽  
Umar Saad Aliyu
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Tellurite Glass ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Gap Energy ◽  
Xrd Method ◽  
Nonlinear Pattern

Borotellurite glass had been widely applied in the field of optical communications and devices. In this work, holmium oxides doped borotellurite glass had been successfully fabricated via conventional melt-quenched technique. The structural properties of holmium doped tellurite glass were found using x-ray diffraction (XRD) method. The nonexistence of sharp peaks in XRD pattern shows that the inclusion of holmium tellurite glass leads to the formation long range of disorderness. The optical properties of the glass system such as refractive index and optical band gap energy are investigated using UV-Vis spectrophotometer. The value of refractive index is found in nonlinear trend along with holmium oxides concentration. It is found that the refractive index is more than 2 at 0.01, 0.03 and 0.04 of holmium concentrations. The optical band gap energy was found in similar trend with refractive index which is in nonlinear pattern.

scholarly journals The Effects of Sn-Doping on a-Fe2O3 Nanostructures Properties

2018 ◽  
Vol 7 (3.11) ◽  
pp. 34
Author(s):  
W R.W. Ahmad ◽  
M H. Mamat ◽  
A S. Zoolfakar ◽  
Z Khusaimi ◽  
M M. Yusof ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electrical Properties ◽  
Tin Oxide ◽  
Glass Substrate ◽  
Optical And Electrical Properties ◽  
Immersion Method ◽  
Coated Glass Substrate ◽  
Sn Doping ◽  
Sn Dopant ◽  
Surface Morphologies

In this study, undoped and Sn-doped hematite (α-Fe2O3) nanostructures with variation of Sn (0.5, 1, 2, 3 at. %) were deposited on fluorine doped tin oxide (FTO) coated glass substrate using sonicated immersion method. The effect of Sn-dopant on structural and crystallinity properties were investigated by characterizing FESEM and XRD respectively, while the optical properties were measured by UV-Vis-NIR spectrometer. The surface morphologies from FESEM have shown that the hematite nanostructures were grown uniformly in all samples. However, as the dopant atomic percentage increases, the amount of hematite nanostructure being grown on the FTO decreases. Results demonstrated that the amount of Sn-doping was undoubtedly influence the structural, optical and electrical properties of hematite nanostructures.  

scholarly journals Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

2021 ◽  
Vol 15 (2) ◽  
pp. 128-135
Author(s):  
Thaís Luiz ◽  
Fabio Nakagomi ◽  
Reny Renzetti ◽  
Guilherme Siqueira
Keyword(s):  
Combustion Synthesis ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Cost ◽  
Synthesis Method ◽  
Particle Growth ◽  
Synthesis Temperature ◽  
Band Gap Energy ◽  
Stoichiometric Ratio ◽  
Synthesis Of Nanoparticles ◽  
Microwave Assisted

The microwave assisted combustion synthesis (MACS) as a new, quick and low cost synthesis method was used for preparation of niobium pentoxide (Nb2O5) powders. The present paper investigated the effect of reactant concentrations (ammonium niobium oxalate, urea and ammonium nitrate) on the characteristics of Nb2O5 nanoparticles. Three samples were synthesized with stoichiometric ratio between the fuel and oxidant (C1), excess of oxidant (C2) and excess of fuel (C3). In all samples, Nb2O5 crystalline nanoparticles with irregular morphology were detected. The synthesis of nanoparticles with smaller diameter in the C2 and C3 samples was confirmed by greater values of band gap energy measured through UV-Visible diffuse reflectance spectroscopy (indicating quantum confinement) and by the Rietveld refinement of X-ray diffraction patterns. The results showed that the amounts of oxidant and fuel can change synthesis temperature, influencing the final characteristics of the particles, such as size and existent phases. In these cases the excess of oxidant and fuel in the C2 and C3 samples, respectively, decreases the average synthesis temperature and decelerates the particle growth and the formation of the monoclinic phase.

scholarly journals Synthesis and Optical Manifestation of NiO-Silica Nanocomposite

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
S. Chakrabarty ◽  
K. Chatterjee
Keyword(s):  
Sol Gel ◽  
Size Variation ◽  
Average Diameter ◽  
Xrd Analysis ◽  
Peak Position ◽  
Band Gap Energy ◽  
Strong Emission ◽  
Silica Nanocomposites ◽  
Composite Formation ◽  
Silica Nanocomposite

NiO-silica nanocomposites with average diameter ranging from 2–40 nm were prepared by sol-gel method followed by the heat treatment varying from 400°C to 1000°C. The details of morphology and crystalline nature of all the as prepared samples were characterized by TEM, HRTEM, and XRD analysis. The planes obtained from SAED pattern supports the planes originated from XRD study. From the optical absorption study, it is revealed that the band gap energy of NiO can extensively be manipulated by composite formation with silica and the size variation of that nanocomposite. Absorption peak position varies almost linearly with the oxidation temperature of the samples. Photoluminescence spectroscopy reveals that NiO-silica nanocomposite, prepared at 600°C and below, shows strong emission at 3.62 eV, but the nanocomposites with bigger size greatly hinder the effect of selective emissivity.

scholarly journals Synthesis of 3D-porous scaffold from cockle shells waste-based hydroxyapatite with addition silica from tin tailings

2021 ◽  
Vol 926 (1) ◽  
pp. 012044
Author(s):  
F Afriani ◽  
J Evi. ◽  
R A Rafsanjani ◽  
R Amelia ◽  
M Hudatwi ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
Goodness Of Fit ◽  
Porous Scaffold ◽  
Raw Materials ◽  
Synthesis Method ◽  
Decomposition Temperature ◽  
Porous Scaffolds ◽  
Xrd Pattern ◽  
Replication Method ◽  
Tailings Sand

Abstract This study aims to synthesize a porous scaffold based on hydroxyapatite and silica using the polymer sponge replication method. In bone tissue engineering technology, the development of porous scaffolds is a topic that is intensively studied because it is expected to be a solution to various problems of conventional bone therapy. In addition to proposing a porous scaffold synthesis method, we also utilize natural waste-based materials such as cockle shells and tin tailings as raw materials in this research. Investigation through x-ray diffraction (XRD) pattern with the goodness of fit coefficient, X 2 = 0.09 shows that the coprecipitation method is effective for the synthesis of hydroxyapatite. Analysis of XRD pattern of tin tailings sand with a value of X 2 = 0.008 showed that the diffraction pattern was related to silica with space group P 41 21 2. The polymer sponge replication method with polyurethane template succeeded in obtaining scaffolds with macropores above 300 μm. Based on the diffraction pattern of the three porous scaffolds prepared with different percentages of HA, it is known that all porous scaffolds have peaks related to HA and silica. It indicates that the decomposition temperature of polymer does not provide sufficient energy for the HA and silica to transform or react chemically.

scholarly journals Synthesis and Infrared Performance of SiB6 Powder through “Chemical Oven” Self-Propagating Combustion

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Shuang Shuang ◽  
Fengxia Yang ◽  
Zhiwei Li ◽  
Jiangtao Li ◽  
Xiangmin Meng
Keyword(s):  
Near Infrared ◽  
Integral Intensity ◽  
Synthesis Method ◽  
Average Diameter ◽  
Raw Material ◽  
Infrared Range ◽  
Severe Condition ◽  
Molar Ratios ◽  
Whole Process ◽  
Maximum Reaction

SiB6 powders were prepared by the “chemical oven” method from Si and B powders. Here combustion with acid pickling “two-step” mode replaces the traditional synthesis method which helps to avoid severe condition of high temperature and high pressure. It could realize maximum reaction temperature to about 2000°C, and the whole process just needs ∼30 s. The average diameter of products is ∼10 μm. And the raw material Si and B are ∼3 μm and ∼20 μm, respectively. The infrared emissivity of products was evaluated by UV-vis spectrum with absorption band around 250∼2500 nm. All five samples show higher emissivity over UV-visible light range with lower emissivity over near-infrared range. Typically, the sample’s Si/B ratio of 1 : 1 shows highest integral intensity for about 0.85 compared with other molar ratios. It can be used as a more simple and effective method to obtain infrared ceramic SiB6 with high emissivity.

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