FeAl2O4 Nanopowders; Structural Analysis and Band Gap Energy

2017 ◽  
Vol 36 (8) ◽  
pp. 789-793 ◽  
Author(s):  
Morteza Enhessari

AbstractNanoscale FeAl2O4 was successfully synthesized via sol–gel method. The sol constituents containing iron and aluminum cations were formed homogenously in stearic acid gel (formation of organic precursor). The pure structural analysis and the size of the spinels were confirmed by X-ray diffraction (XRD). It was observed that the size of the nanoscale materials obtained at around 30–40nm. The micrographs of FeAl2O4 evidenced the homogenous and nanosize formation of spinel. The semiconducting behavior of this mixed metal oxide was observed at 3.14eV based on the band gap energy (Eg). The final nanoscale materials exhibited a superparamagnetic behavior with a saturation magnetization of 9.8 emu/g at applied field of 10 kOe.

2012 ◽  
Vol 545 ◽  
pp. 161-164
Author(s):  
Rusdi Roshidah ◽  
Abd Rahman Azilah ◽  
Norlida Kamarulzaman

ZnO is known as an inorganic material that has a variety of morphologies. The morphologies of the ZnO are much influenced by the synthesis route. In this work, two ZnO nanomaterials were prepared by the sol-gel route and the effect of detergent on the morphology and optical band gap of ZnO materials were investigated. The synthesized ZnO materials were characterized using Simultaneous Thermogravimetric Analyzer (STA), X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The UV-Vis spectrophotometer is used to determine the optical band gap. The results show that the presence of detergent affected the morphology of the ZnO from nanorods to nano-flakes. The band gap energy of the ZnO were also reduced from 3.14 ev to 2.98 eV from the nanorod to the nanoflakes.


2021 ◽  
Vol 317 ◽  
pp. 95-99
Author(s):  
Muhammad Noorazlan Abd Azis ◽  
Halimah Mohamed Kamari ◽  
Suriani Abu Bakar ◽  
Azlina Yahya ◽  
Umar Saad Aliyu

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.


2015 ◽  
Vol 1131 ◽  
pp. 237-241 ◽  
Author(s):  
Akkarat Wongkaew ◽  
Chanida Soontornkallapaki ◽  
Naritsara Amhae ◽  
Wichet Lamai

This work aims to study the effect of ZnO containing in TiO2/SiO2 film on the superhydrophilic property after exposed to different types of light. The metal solutions were prepared by sol-gel technique and the film was deposited on glass slides by dip coating method. The parameter studied was the amount of ZnO in the TiO2/SiO2 film. The contents of ZnO were 5-20% weight (increased by 5%). The amount of TiO2 was constant at 30% weight. The obtained films were analyzed for their roughness. The results indicated that film roughness changed according to the ZnO contents. With 5%ZnO in the thin film, the roughness was 0.726 nm while 20%ZnO obtained the roughness of 2.128 nm. UV-Vis spectrophotometer was used for measuring of transmittance of films. At wavelength of 550 nm, the transmittances of each film were greater than 90%. Band gap energy of each film was calculated from the transmittance data. It was found that the average band gap energy of the films was 2.47 eV. Then, the films contained various amount of ZnO were grouped into 2 sets. The first set was exposed to visible light while the other set was exposed to UV. The duration of exposure was 5 hr. Both sets of films after exposed to any light were kept in a black box controlled relative humidity of 85%. Each film was measured contact angle every day. It was found that the 30%TiO2/5%Zn/SiO2 film exposed to visible light showed the best superhydrophilic property. The contact angle was about 0-5° within 3 days. This may due to the reduction of band gap energy in the presence of ZnO in TiO2/SiO2 films to 2.41 eV and the roughness of the film.


2012 ◽  
Vol 622-623 ◽  
pp. 883-888
Author(s):  
Natkritta Boonprakob ◽  
Natda Wetchakun ◽  
Sukon Phanichphant ◽  
Jun Chen ◽  
Burapat Inceesungvorn

Nitrogen-loaded TiO2(N-loaded TiO2), a visible-light driven catalyst, was successfully synthesized by the modified sol-gel method. Physical characterizations of the as-prepared catalysts have been performed by using X-ray diffraction (XRD), Diffuse reflectance UVvisspectroscopy(DRUVvis), Raman spectroscopyand BETspecific surface areain order to obtain structure-activity relationship. Results from Raman spectroscopy clearly suggested that N atoms were incorporated into the TiO2crystal lattice as evidenced by the vibrational peak of TiN in TiO2-xNx.DR UVvis results also suggested that the nitrogen dopant might be responsible for narrowing the TiO2band gap energy, thus resulting in a shift towards the visiblelight region. Photocatalytic activity of N-loaded TiO2evaluated through the degradation of methyl orange (MO)under visible light irradiation (l> 400 nm) indicated that all N-loaded photocatalysts exhibited significantly higher activities than the unloaded TiO2and Degussa P25 TiO2. According to the results from DR UV-vis, XRD and BET studies, the enhanced photoactivity observed from N-loaded samples might be due to a decrease in TiO2band gap energy and/or changes in chemical and physical properties of the materials upon loading with nitrogen.


2017 ◽  
Vol 889 ◽  
pp. 234-238
Author(s):  
Mohd Hasmizam Razali ◽  
Nur Arifah Ismail ◽  
Mahani Yusoff

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.


2020 ◽  
Vol 301 ◽  
pp. 97-102
Author(s):  
Nor Fadilah Chayed ◽  
Nurhanna Badar ◽  
Kelimah Elong ◽  
Norlida Kamarulzaman

Preparation of MgO and Mg0.9Li0.2O materials using self-propagating combustion method are done to investigate the effect of substitution doping on the band gap energy. The synthesis condition has been optimized to obtain pure and single phase of MgO and Mg0.9Li0.2O materials and was confirmed by X-Ray Diffraction (XRD). The morphology obtained from field emission scanning electron microscopy (FESEM) is spherical and rounded polyhedral shape with agglomeration of crystallites for MgO and Mg0.9Li0.2O materials respectively. The crystallite size of MgO and Mg0.9 Li0.2O samples is between 50 nm to 120 nm and 200 nm to 1500 nm respectively. The band gap was determined by UV-Vis NIR spectrophotometer and it was found that the band gap obtained for MgO nanostructure is 6.10 eV which is lower than bulk MgO of 7.8 eV. The presence of Li in the MgO had caused changes in morphology, crystallite size and band gap narrowing to 3.83 eV.


Author(s):  
Anuar Kassim ◽  
Tan Wee Tee ◽  
Ho Soon Min ◽  
Shanthi Monohorn ◽  
Saravanan Nagalingam

PbSe thin films are prepared by chemical bath deposition technique over microscope glass substrates from an aqueous acidic bath containing lead nitrate and sodium selenate. The influence of bath temperature on the properties of PbSe film is investigated. The X-ray diffraction analysis showed the deposited films were polycrystalline and having the (111) orientation. The surface morphology study revealed that the grains have cubic shape crystal. The band gap energy was decreased from 2.0 to 1.3 eV as the bath temperature was increased from 40 to 80°C. The films deposited at 80°C showed good crystallinity and uniformly distributed over the surface of substrate with larger grain sizes. Therefore, the optimum bath temperature is 80°C. Keywords: Lead selenide; X-ray diffraction; Band gap energy; Chemical bath deposition; Thin films DOI: 10.3126/kuset.v6i2.4021Kathmandu University Journal of Science, Engineering and Technology Vol.6. No II, November, 2010, pp.126-132


2012 ◽  
Vol 545 ◽  
pp. 157-160 ◽  
Author(s):  
Nurhanna Badar ◽  
Nor Fadilah Chayed ◽  
Rusdi Roshidah ◽  
Norashikin Kamarudin ◽  
Norlida Kamarulzaman

In this work, the band gap energies of magnesium oxide (MgO) were investigated to see if calcination time affects the band gap energies of the MgO. MgO nanomaterials have been prepared by a sol-gel method. MgO precursors produced were calcined at a temperature of 600 °C for 24 hours and 48 hours. The structural characterization of samples is achieved using X-Ray Diffraction (XRD) and the morphology as well as particle size of MgO were examined by Field Emission Scanning Electron Microscopy (FESEM). UV-Vis NIR spectroscopy was used to determine the band gap energies of the materials. From the results, the band gap energy of the MgO with a longer heating time exhibited a higher value.


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