scholarly journals Preparation and Photocatalytic Properties of CdS and ZnS Nanomaterials Derived from Metal Xanthate

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3313 ◽  
Author(s):  
Neli Mintcheva ◽  
Gospodinka Gicheva ◽  
Marinela Panayotova ◽  
Wilfried Wunderlich ◽  
Aleksandr A. Kuchmizhak ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Energy Band ◽  
Photocatalytic Properties ◽  
Cubic Phase ◽  
Sulfur Source ◽  
Energy Band Gap ◽  
Simple Method ◽  
Vis Spectroscopy ◽  
Metal Xanthate

In this paper, we report a new, simple method for the synthesis of CdS and ZnS nanoparticles (NPs) prepared in a basic aqueous medium using metal xanthate as the sulfur source. The structure, morphology, size distribution, optical band gap, and photocatalytic properties of the newly obtained nanomaterials were investigated by UV-Vis spectroscopy, X-ray diffraction, and transmission electron microscopy. The results show that both CdS and ZnS crystallized in cubic phase and formed NPs with average sizes of 7.0 and 4.2 nm for CdS and ZnS, respectively. A blue shift of UV-Vis absorbance band and higher energy band gap values were observed for both materials in comparison with their bulk counterparts, which is in accordance with the quantum confinement effect. The as-prepared nanomaterials were tested in visible-light driven photocatalytic decomposition of methylene blue (MB). After irradiation for 180 min, the degradation rate of MB with a concentration of 8 × 10−6 mol/L mixed with a photocatalyst (CdS or ZnS, both 10 mg in 100 mL solution of MB) was found to be 72% and 61%, respectively. The CdS NPs showed better photocatalytic activity than ZnS, which could be explained by their lower energy band gap and thus the ability to absorb light more efficiently when activated by visible-light irradiation.

Energy Band Gap Modulation in Nd-Doped BiFeO3/SrRuO3 Heteroepitaxy for Visible Light Photoelectrochemical Activity

2018 ◽  
Vol 11 (1) ◽  
pp. 1655-1664 ◽  
Author(s):  
Kok Hong Tan ◽  
Yun-Wen Chen ◽  
Chien Nguyen Van ◽  
Hongliang Wang ◽  
Jhih-Wei Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap ◽  
Photoelectrochemical Activity ◽  
Band Gap Modulation

The Study of Energy Band Gap of In[sub x]Al[sub y]Ga[sub 1−x−y]N Quaternary Alloys using UV-VIS Spectroscopy

2009 ◽  
Author(s):  
N. H. Abd. Raof ◽  
S. S. Ng ◽  
H. Abu Hassan ◽  
Z. Hassan ◽  
Mohamad Rusop ◽  
...  
Keyword(s):  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap ◽  
Quaternary Alloys ◽  
Vis Spectroscopy

N-Doped Titanium Monoxide Nanoparticles with TiO Rock-Salt Structure, Low Energy Band Gap, and Visible Light Activity

2010 ◽  
Vol 22 (12) ◽  
pp. 3704-3711 ◽  
Author(s):  
Pardis Simon ◽  
Bruno Pignon ◽  
Baoji Miao ◽  
Servane Coste-Leconte ◽  
Yann Leconte ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Rock Salt ◽  
Energy Band ◽  
Low Energy ◽  
Titanium Monoxide ◽  
Energy Band Gap ◽  
Rock Salt Structure ◽  
Light Activity ◽  
Salt Structure

scholarly journals Synthesis of Oxygen Deficient TiO2 for Improved Photocatalytic Efficiency in Solar Radiation

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 904
Author(s):  
Kassim Olasunkanmi Badmus ◽  
Francois Wewers ◽  
Mohammed Al-Abri ◽  
Mohd Shahbaaz ◽  
Leslie F. Petrik
Keyword(s):  
Solar Radiation ◽  
Visible Light ◽  
Band Gap ◽  
Tio2 Nanoparticles ◽  
Energy Band ◽  
High Energy ◽  
Orange Ii ◽  
Tio2 Photocatalyst ◽  
Energy Band Gap ◽  
Visible Light Active

The photocatalytic activities of TiO2 have been limited mainly to absorbing in the ultraviolet spectrum which accounts for only 5% of solar radiation. High energy band gap and electron recombination in TiO2 nanoparticles are responsible for its limitations as a photocatalyst. An oxygen deficient surface can be artificially created on the titanium oxide by zero valent nano iron through the donation of its excess electrons. A visible light active TiO2 nanoparticle was synthesized in the current investigation through simple chemical reduction using sodium boro-hydride. The physical and textural properties of the synthesized oxygen deficient TiO2 photocatalyst was measured using scanning/ transmission electron microscopy while FTIR, XRD and nitrogen sorption methods (BET) were employed for its further characterizations. Photochemical decoloration of orange II sodium dye solution in the presence of the synthesized TiO2 was measured using an UV spectrophotometer. The resulting oxygen deficient TiO2 has a lower energy band-gap, smaller pore sizes, and enhanced photo-catalytic properties. The decoloration (88%) of orange (II) sodium salt solution (pH 2) under simulated solar light was possible at 20 min. This study highlights the effect of surface oxygen defects, crystal size and energy band-gap on the photo-catalytical property of TiO2 nanoparticles as impacted by nano zero valent iron. It opens a new window in the exploitation of instability in the dopant ions for creation of a visible light active TiO2 photocatalyst.

scholarly journals Structural, Optical and Electrical Characterizations of Cr-doped CuO Thin Films

2021 ◽  
Author(s):  
Silan BATURAY ◽  
ilhan CANDAN ◽  
Cihat OZAYDIN
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spin Coating ◽  
Energy Band ◽  
Wavelength Region ◽  
Light Sensitivity ◽  
Soda Lime Glass ◽  
Energy Band Gap ◽  
Vis Spectroscopy ◽  
Cr Doping

Abstract The polycrystalline copper oxide (CuO) thin films have been produced using method of spin coating onto the soda lime glass (SLG) as well as substrate of p-type Si (1 0 0) wafers at 500 ºC in furnace. The obtained undoped and Cr doped thin films of CuO have been comprehensively characterized via X-ray diffraction (XRD), ultraviolet–vis (UV–vis) spectroscopy, the current–voltage ( I – V ) and capacitance–voltage ( C – V ) characteristics for providing information on quality of the crystalline nature, change in energy band gap and electrical properties, respectively. Structural analysis results which obtained from XRD data demonstrate that CuO films conjunction with Cr doping indicated that all thin films have monoclinic polycrystalline nature, with two main peaks (002) and (111) with d hkl about 2.52 and 2.32 Å, respectively. The transmittance and energy band gap value of undoped and Cr doped thin films of CuO ranging in varying concentration ratio have been determined in the wavelength region of 300 to 1100 nm. UV–vis spectrum analysis results indicate that both transmittance value and energy band gap of the CuO films is changed with increasing Cr doping ratio in CuO solution at room temperature. The I–V and C–V characteristic of Cr:CuO/p-Si diodes were associated with the CuO/p-Si diodes. It is seen that doping of Cr had a significant change onv the obtained devices’ performance. Thus, the Cr:CuO/p-Si diodes generated by 1% Cr doping using spin coating method had the highest light sensitivity compared with those of the other diodes.

Optical properties of PVP/ZnO composite thin films

2017 ◽  
Vol 1 (82) ◽  
pp. 5-11 ◽  
Author(s):  
T. Tański ◽  
W. Matysiak
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Zno Nanoparticles ◽  
Energy Band ◽  
Composite Coatings ◽  
Energy Band Gap ◽  
Thin Coatings ◽  
Pure Polymer ◽  
Vis Spectroscopy ◽  
Coating Method

Purpose: The aim of the work was the preparation of thin composite layers from PVP polymer doped by ZnO nanoparticles using the spin coating method and the analysis of the applied reinforcing phase on the morphology and optical properties of obtained composites. Design/methodology/approach: To analyse the morphology of thin coatings a technique of surface topography imaging using the atomic force microscopy (AFM) was applied. Analysis of the optical properties was conducted using absorbance spectrum in function of wavelength for all produced thin coatings using UV-Vis spectroscopy. Findings: AFM results show that mass concentration of ZnO nanoparticles of 10% in a solution of PVP/EtOH polymers has a meaningful influence on the morphology of the surface of the PVP/ZnO composite coatings. Using obtained absorbance spectra, the width of the band gap of the manufactured composite coatings were determined which were compared with a band gap values of pure polymer and used reinforcing phase. Practical implications: The analysis of the values of the energy band gap of the manufactured materials showed that both for pure polymer and composite coatings values of energy band gap are similar approx. 4 eV at the same time decrease the degree of absorption of electromagnetic radiation caused by the increasing concentration of the reinforcing phase, which indicates the broad possibilities of application of this type of the material.

The Study of Energy Band Gap of Al[sub x]In[sub y]Ga[sub 1−x−y]N Quaternary Alloys Using UV-VIS Spectroscopy

2010 ◽  
Author(s):  
M. A. Abid ◽  
H. Abu Hassan ◽  
Z. Hassan ◽  
S. S. Ng ◽  
N. H. Abd. Raof ◽  
...  
Keyword(s):  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap ◽  
Quaternary Alloys ◽  
Vis Spectroscopy

scholarly journals No Resistive Normal Electrons in Beginning Superconducting States

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1512
Author(s):  
Changho Seo ◽  
Seongsoo Cho ◽  
Je Huan Koo
Keyword(s):  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap

We investigate why normal electrons in superconductors have no resistance. Under the same conditions, the band gap is reduced to zero as well, but normal electrons at superconducting states are condensed into this virtual energy band gap.

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