scholarly journals Immobilization of cobalt doped rutile TiO2 on carbon nanotubes walls for efficient photodegradation of 2,4-dichlorophenol under visible light

2019 ◽  
Author(s):  
Pejman Monazzam ◽  
azadeh ebrahimian pirbazari ◽  
Behnam Fakhari Kisomi ◽  
Ziba Khodaee
Keyword(s):  
Carbon Nanotubes ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Band Gap Energy ◽  
Cobalt Doping ◽  
Average Pore ◽  
X Ray ◽  
Gap Energy

In this work, we focused on improvement of rutile-type TiO2 degradation efficiency by cobalt doping and decorating on carbon nanotubes walls (CNTs) (Co-TiO2/CNTs). X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), diffuse reflectance spectroscopy (DRS), and nitrogen physisorption were used to characterize the prepared samples. The XRD results indicated after cobalt doping, we obtained rutile phase as the major phase for cobalt containing samples. The band gap energy of the synthesized samples were calculated by Kubelka-Munk equation using diffuse reflectance spectra. The surface area of the samples was obtained by BET model and average pore diameter and pore volume of the samples were extracted from desorption branch of BJH model. The effectiveness of the samples was examined through degradation of 2,4-dichlorophenol (2,4-DCP) as a model of organic pollutants under visible light. We achieved 27% and 50% visible light degradation of 2,4-DCP in the presence of pure TiO2 and Co-TiO2/CNTs after 180 min irradiation, respectively. The high visible light activity of Co-TiO2/CNTs sample can be approved that the presence of cobalt and CNTs reduce the band gap energy and sensitize TiO2 surface to visible light respectively. The mechanism for degradation of 2,4-DCP by Co-TiO2/CNTs photocatalyst under visible light is proposed.

Study on Band Gap Energy of F Doped TiO2 Nanotubes

2017 ◽  
Vol 889 ◽  
pp. 234-238
Author(s):  
Mohd Hasmizam Razali ◽  
Nur Arifah Ismail ◽  
Mahani Yusoff
Keyword(s):  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Small Diameter ◽  
Ultra Violet ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gap Energy ◽  
Transmission Electron ◽  
Xrd Patterns

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.

scholarly journals Automated method for the determination of the band gap energy of pure and mixed powder samples using diffuse reflectance spectroscopy

Heliyon ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. e01505 ◽  
Author(s):  
A. Escobedo-Morales ◽  
I.I. Ruiz-López ◽  
M.deL. Ruiz-Peralta ◽  
L. Tepech-Carrillo ◽  
M. Sánchez-Cantú ◽  
...  
Keyword(s):  
Band Gap ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Band Gap Energy ◽  
Mixed Powder ◽  
Gap Energy ◽  
Automated Method ◽  
Powder Samples

scholarly journals Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
P. Nyamukamba ◽  
L. Tichagwa ◽  
S. Mamphweli ◽  
L. Petrik
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Of

Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

Visible-Light-Induced Photocatalytic Activity of Boron-Doped BiVO4

2014 ◽  
Vol 809-810 ◽  
pp. 890-894
Author(s):  
Dan Li ◽  
Lian Wei Shan ◽  
Gui Lin Wang ◽  
Li Min Dong ◽  
Wei Li ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Reflectance Spectroscopy ◽  
Scheelite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Doped

Boron-BiVO4 samples were synthesized by sol-gel method. They were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction. Photocatalytic activity of the obtained BiVO4 samples was investigated through degrading methylene blue (MB). The results reveal that boron-BiVO4 catalysts have monoclinic scheelite structure. The BiVO4 and Co-BiVO4 photocatalysts were responsive to visible light. Co-BiVO4 photocatalyst showed higher photocatalytic activity than pure BiVO4, resulting in the significantly improved efficiency of degradation of MB.

scholarly journals Use and misuse of the Kubelka-Munk function to obtain the band gap energy from diffuse reflectance measurements

2021 ◽  
pp. 114573
Author(s):  
Salmon Landi ◽  
Iran Rocha Segundo ◽  
Elisabete Freitas ◽  
Mikhail Vasilevskiy ◽  
Joaquim Carneiro ◽  
...  
Keyword(s):  
Band Gap ◽  
Diffuse Reflectance ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Munk Function ◽  
Reflectance Measurements

Effect of ZnO on a Superhydrophilic Self-Cleaning Properties of TiO2/SiO2 Thin Film on Glass Slide Substrate

2015 ◽  
Vol 1131 ◽  
pp. 237-241 ◽  
Author(s):  
Akkarat Wongkaew ◽  
Chanida Soontornkallapaki ◽  
Naritsara Amhae ◽  
Wichet Lamai
Keyword(s):  
Thin Film ◽  
Contact Angle ◽  
Visible Light ◽  
Band Gap ◽  
Sol Gel ◽  
Dip Coating ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Coating Method ◽  
Dip Coating Method

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.

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