Femtosecond Diffuse Reflectance Spectroscopy of Aqueous Titanium(IV) Oxide Suspension: Correlation of Electron-Hole Recombination Kinetics with Photocatalytic Activity

1998 ◽  
Vol 27 (7) ◽  
pp. 579-580 ◽  
Author(s):  
Bunsho Ohtani ◽  
Robert M. Bowman ◽  
D. Philip Colombo Jr. ◽  
Hiroshi Kominami ◽  
Hidenori Noguchi ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Electron Hole ◽  
Recombination Kinetics ◽  
Hole Recombination

scholarly journals Synthesis and photocatalytic activity of ZnO/CuO composite for the degradation of methyl blue under vilsible light iradiation

2020 ◽  
Vol 9 (3) ◽  
pp. 94-100
Author(s):  
Kim Nguyen Van ◽  
Nga Nguyen Thi Viet ◽  
Tuyen Vo Thi Thanh ◽  
Vien Vo
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Photogenerated Electron ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Microwave System ◽  
Direct Formation

Composite ZnO/CuO was prepared by direct formation of ZnO from Zn(OOCCH3)2 precursor in the presence of CuO with the assistant of the microwave system. The obtained composite was characterized by X-Ray Diffraction (XRD) and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-vis DRS), which shows that the composite with a bandgap of 3.27 eV contains two components, ZnO and CuO. The photocatalytic activity of ZnO/CuO was assessed by the degradation of methylene blue (MB) in water under visible light, shows that the photocatalytic activity for the ZnO/CuO composite was remarkably improved compared to single ZnO and CuO. This result is attributed to the reduced recombination rate of photogenerated electron-hole pairs by the presence of CuO in the composite, therefore photocatalysis activity increases.

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.

The Effect of Chromium on the Optical Properties and Photoactivity of Nano-Particulate Rutile

2012 ◽  
Vol 554-556 ◽  
pp. 502-506 ◽  
Author(s):  
Li Wei Wang ◽  
Terry A. Egerton
Keyword(s):  
Optical Properties ◽  
Photocatalytic Activity ◽  
Reflectance Spectroscopy ◽  
Electron Trapping ◽  
Electron Hole ◽  
High Chromium ◽  
Chromium Doping ◽  
Chromium Addition ◽  
Co Precipitation ◽  
Hole Recombination

Chromium doped rutile TiO2was synthesized by either co-precipitation or impregnation (surface-doping) and characterized by XRD and reflectance spectroscopy. Chromium addition did not change the TiO2structure nor did the structure of the co-precipitated products differ from that of the impregnated samples. However, chromium doping moved the absorption of both sets of products into the visible and significantly affected the TiO2photocatalytic activity for isopropanol (IPA) oxidation. At high chromium concentrations the photoactivity of the co-precipitated samples was reduced by a larger amount than that of the impregnated samples; this was attributed to a higher concentration of Cr3+ions in the rutile lattice. Unexpectedly, increased photoactivity was measured for low Cr levels of surface-doped rutile. This may be caused by increased electron-trapping, at surface Cr6+ions, and correspondingly reduced, electron-hole recombination.

scholarly journals Template-Free Synthesis of Star-Like ZrO2 Nanostructures and Their Application in Photocatalysis

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xue-Yu Tao ◽  
Jie Ma ◽  
Rui-Lin Hou ◽  
Xiang-Zhu Song ◽  
Lin Guo ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Hydrothermal Process ◽  
Photocatalytic Property ◽  
Reflectance Spectroscopy ◽  
Raw Material ◽  
Narrow Bandgap ◽  
Excellent Photocatalytic Activity ◽  
Template Free

Star-like nano-ZrO2 has been synthesized using Zr(NO3)4·5H2O as zirconium source by a hydrothermal process without any template and surfactant. The structure of the as-prepared ZrO2 powder was investigated by multiple advanced analytical methods. The results showed that CH3COO− and NO3− had great effects on the formation of star-like ZrO2 nanostructures. The as-prepared ZrO2 had a superior catalytic activity, and the reason for it was analyzed by UV-Vis diffuse reflectance spectroscopy. The effect of raw material ratios on the photocatalytic property of ZrO2 was studied. The synthesized ZrO2 showed a narrow bandgap (3.50–3.85 eV) and an excellent photocatalytic activity, and the degradation of RhB was up to nearly 100% in 30 min with this photocatalyst.

Synthesis and Photocatalytic Properties of Flower-Like ZnIn2S4 Microspheres by a Solvothermal Method

2014 ◽  
Vol 881-883 ◽  
pp. 1101-1104 ◽  
Author(s):  
Min Jie Zhou ◽  
Peng Cui
Keyword(s):  
Photocatalytic Activity ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Diffuse Reflectance ◽  
Solvothermal Method ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this work, flower-like ZnIn2S4 microspheres were synthesized using a solvothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS) techniques. The photocatalytic activity of the ZnIn2S4 microspheres was investigated. The ZnIn2S4 microspheres exhibit much higher photocatalytic activity than pure P25 TiO2.

Fabrication of Pr-Doped Bi2O3 with Enhanced Photocatalytic Performance under Visible Light

2012 ◽  
Vol 550-553 ◽  
pp. 196-199
Author(s):  
Ze Wan ◽  
Fa Mei Feng ◽  
Jian Zhang Li ◽  
Jin Jin He ◽  
Jun Bo Zhong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Methyl Orange Solution ◽  
Reflectance Spectroscopy ◽  
Surface Photovoltage Spectroscopy ◽  
Orange Solution

This paper reveals that photocatalytic activity of Bi2O3 under visible light towards the decolorization of Methyl Orange solution can be greatly enhanced by doping Pr into the lattice of Bi2O3 using a sol-gel method. The photocatalysts were characterized by BET, UV-Vis diffuse reflectance spectroscopy and surface photovoltage spectroscopy (SPS), respectively. The result shows that 4%Pr doped Bi2O3 possesses the best photocatalytic activity under visible light.

Fabrication and Photocatalytic Performance of Titanium Dioxide Nanoparticle/Polymethylmethacrylate

2013 ◽  
Vol 331 ◽  
pp. 461-464
Author(s):  
Sheng Hui Yan ◽  
Yu Ting Zhang
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Batch Reactor ◽  
Reflectance Spectroscopy ◽  
Titanium Dioxide Nanoparticle ◽  
Gaseous Benzene

t has been found that the photocatalytic activity of TiOB2B toward the decomposition of gaseous benzene in a batch reactor can be greatly improved by modifying TiOB2 Bin the presence of 3-(trimethoxysilyl) propylmethacrylate (MPS). The prepared photocatalyst (PMMA-TiOB2B) was characterized by FTIR, UV/Vis diffuse reflectance spectroscopy and XPS. PMMA-TiOB2 Bdemonstrates 2.3 times the photocatalytic activity of that of TiOB2B.

PVA(Polyvincyl Acohol)-assisted Hydrothermal Preparation of Bi25FeO40 and Its Photocatalytic Activity

2009 ◽  
Vol 1217 ◽  
Author(s):  
Li Jianmin ◽  
Juyue Song ◽  
Jianguo Chen ◽  
Shengwen Yu ◽  
Dengren Jin ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Organic Contaminants ◽  
Diffuse Reflectance ◽  
Single Phase ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
High Photocatalytic Activity ◽  
Photocatalytic Decomposition ◽  
Hydrothermal Preparation ◽  
Degradation Of Methyl Orange

AbstractA PVA-assisted hydrothermal synthesis route was utilized to fabricate single-phase Bi25FeO40 crystallites.X-ray diffraction results indicated that sillenite Bi25FeO40 have been synthesized at the temperature of 200 ℃ using the KOH concentration of 7 M. Scanning electron microscopy showed the morphology of the as-prepared products were cubic shape with side length of 26μm. The band gap of Bi25FeO40 was determined to be 1.8 eV (688 nm) by using UV-vis diffuse reflectance spectroscopy. It was found that Bi25FeO40 exhibited a high photocatalytic activity for the degradation of methyl orange under UV-Vis irradiation, being a potential material for photocatalytic decomposition of organic contaminants.

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