scholarly journals Catalytic Activity of a Composition Based on Strontium Bismuthate and Bismuth Carbonate at the Exposure to the Light of the Visible Range

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
K. S. Makarevich ◽  
A. V. Zaitsev ◽  
O. I. Kaminsky ◽  
E. A. Kirichenko ◽  
I. A. Astapov
Keyword(s):  
Diffuse Reflection ◽  
Wide Band ◽  
Visible Range ◽  
Powder Materials ◽  
Reflection Spectra ◽  
Narrow Gap ◽  
Electron Hole ◽  
Organic Precursor ◽  
Molar Ratios ◽  
Semiconductor System

This paper presents the results pertaining to studying the properties of the photocatalytically active composition of strontium bismuthate SrBi2.70O5.05, SrBi2.90O5.35, and SrBi3.25O5.88 and bismuth carbonate (BiO)2CO3 in molar ratios 1/0.67, 1/0.56, and 1/0.37, respectively. These compositions are obtained through pyrolytic synthesis from organic precursor complexes of strontium and bismuth with sorbitol. It has been established that the synthesised powder materials absorb the light of the visible range up to 500 nm owing to the presence of a narrow-gap semiconductor strontium bismuthate. The presence of a wide-band semiconductor (BiO)2CO3 ensures an effective separation of electron-hole pairs. The diffuse reflection spectra (DRS) of compositions differ from the analogous spectra of a mechanical mixture of these semiconductor phases with the same composition, which allows one to assume the heterostructural structure of the semiconductor system. The same heterostructure is confirmed by the results of mapping. Catalytic particles that are synthesised at a temperature of 500°C containing 27 mass% (BiO)2CO3 (corresponding to SrBi2.9O5.35/(BiO)2CO3 = 1/0.56) have the greatest activity with respect to the photodecomposition of methylene blue (MB). The possibility of controlling the optical properties and photocatalytic activity of the composition is depicted due to the joint formation of the strontium bismuthate phase and the bismuth carbonate phase.

Preparation of Visible-Light-Responsive TiO2-xNx Photocatalyst by a Very Simple Method

2011 ◽  
Vol 383-390 ◽  
pp. 3188-3191
Author(s):  
Han Jie Huang ◽  
Wen Long She ◽  
Ling Wen Yang ◽  
Hai Peng Huang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflection ◽  
Ammonia Solution ◽  
Reflection Spectra ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Light Excitation

A visible-light-responsive TiO2-xNx photocatalyst was prepared by a very simple method. Ammonia solution was used as nitrogen resource in this paper. The TiO2-xNx photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), UV-Vis diffuse reflection spectra (DRS), and X-ray photoelectron spectroscopy (XPS). The ethylene was selected as a target pollutant under visible light excitation to evaluate the activity of this photocatalyst. The new prepared TiO2-xNx photocatalyst with strong photocatalytic activity under visible light irradiation was demonstrated in the experiment.

Spectroscopic Analysis and Synthesis of Wide Band Gap CdS Quantum Dots Using Colloidal Synthesis Technique at Low Temperature

2009 ◽  
Vol 67 ◽  
pp. 191-196 ◽  
Author(s):  
Lubna Hashmi ◽  
M.S. Qureshi ◽  
R.N. Dubey ◽  
M.M. Malik ◽  
Ishrat Alim ◽  
...  
Keyword(s):  
Low Temperature ◽  
Band Gap ◽  
Spectroscopic Analysis ◽  
Quantum Confinement Effect ◽  
Wide Band ◽  
Colloidal Synthesis ◽  
Visible Range ◽  
Wide Band Gap ◽  
Synthesis Technique ◽  
Analysis And Synthesis

A broad range of II-VI materials has been investigated in order to produce light in the full visible range for optoelectronic applications. The present investigation was carried out for the spectroscopic analysis and synthesis of wide band gap cadmium sulfide nanoparticles. Large-band gap semiconductors have the added advantage in that; they can support higher electric field before breaking down, which means that they can be used for high-power electronic devices.Synthesis has been carried out using colloidal synthesis technique at low temperature. The size, stabilization and optical properties were studied using UV-vis Spectrophotometer and Spectroflourometer. Further, the structural studies of synthesized powder were carried out using X-ray diffraction technique; which also confirms the formation of desired product. The capping ligand and the impurities present in the sample were characterized by Fourier transform infra red spectroscopy. Synthesized CdS powder dispersed in aqueous media gave the value of 193 nm for the onset wavelength using UV-vis spectrophotometer, which is significantly blue-shifted compared to bulk CdS and shows the quantum confinement effect. From the onset wavelength the radius of CdS quantum dot calculated using the Brus equation was found to be ca. 0.7 nm.

Device for determining the diffuse-reflection spectra of various kinds of wood

2007 ◽  
Vol 74 (5) ◽  
pp. 351
Author(s):  
V. A. Anchukov ◽  
Yu. V. Ilyasov ◽  
G. G. Gorbunov ◽  
S. S. Gulidov ◽  
A. P. Lappo ◽  
...  
Keyword(s):  
Diffuse Reflection ◽  
Reflection Spectra

Comparative analysis of anti-reflection coatings on solar PV cells through TiO2 and SiO2 nanoparticles

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rajkamal Sivakumar ◽  
Prabhakaran Gopalakrishnan ◽  
Mohamed Sikkander Abdul Razak
Keyword(s):  
Refractive Index ◽  
Solar Cells ◽  
Research Work ◽  
Photon Absorption ◽  
Visible Range ◽  
Bandgap Energy ◽  
Solar Pv ◽  
Electron Hole ◽  
Content Type ◽  
Vis Spectroscopy

Purpose Photon absorbance and reflectance are the most important parameters for the recombination of electron-hole pairs. Bandgap energy plays a vital role in photon absorption. That is, the photons with energy greater than band gap energy are absorbed. Also, the refractive index of semiconductors is responsible for photon reflection, as the surface with the highest refractive index will reflect more photons than a surface with have a low refractive index. The purpose of this paper is to improvise the absorbance and reduce the reflectance of photons on the front surface of solar cells. Design/methodology/approach Photon reflection is results in reduction in electron-hole pair generation due to the high refractive index of semiconductive materials. To overcome this problem, an Anti-reflection (AR) coating of TiO2 and SiO2 is undertaken on solar cells through the Sol-spin coating method. Finally, the effectiveness of the Anti-Reflection coating is scrutinized through UV Vis-Spectroscopy, which provides details regarding reflectance, absorbance and bandgap energy characteristics. Findings UV–visible spectroscopy was used to measure the responses from the samples. The samples responded to the ultraviolet and visible range of electromagnetic radiation perfectly. UV spectroscopy was done before and after the antireflection coating of TiO2 and SiO2 over the solar cell to find their corresponding extreme reflectance and absorbance values. The effects of TiO2 and SiO2 were evaluated from the results. Originality/value In this research work, the authors have done anti-reflection coating over solar cells with nanoparticles derived from sol-gel process. Absorbance of photons observed through diffuse reflection method.

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