scholarly journals Enhanced Photoreduction Activity of Carbon Dioxide over Co3O4/CeO2Catalysts under Visible Light Irradiation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ying Huang ◽  
Chang-Feng Yan ◽  
Chang-Qing Guo ◽  
Shi-Lin Huang
Keyword(s):  
Carbon Dioxide ◽  
Charge Transfer ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Narrow Band ◽  
Ethanol Yield ◽  
Combustion Method ◽  
Electron Hole ◽  
Glycine Nitrate Combustion

A series of new two semiconductor catalysts, Co3O4/CeO2, were prepared by glycine-nitrate combustion method for photocatalytic reduction of carbon dioxide to produce methanol and ethanol under visible light (λ>400 nm) irradiation. The catalysts were characterized by BET, UV-vis spectra, XRD, SEM, PL, and XPS and the results indicated that the catalyst with 5 wt.% of Co3O4has the highest yield among all kinds of tests with the methanol yield of 1.52 μmol·g−1·h−1and the ethanol yield of 4.75 μmol·g−1·h−1, which are about 2.34 and 1.71 times as large as those of CeO2. However, methanol and ethanol can hardly be detected for Co3O4under the same condition because of its too narrow band gap. The improvement of the photoreduction activity of Co3O4doped CeO2was caused by the separation of electron-hole pairs of Co3O4/CeO2and charge transfer between Co3O4and CeO2, mimicking the Z-scheme in photosynthesis.

scholarly journals Realizing high hydrogen evolution activity under visible light using narrow band gap organic photocatalysts

2021 ◽  
Author(s):  
Changzhi Han ◽  
Peihua Dong ◽  
Haoran Tang ◽  
Peiyun Zheng ◽  
Chong Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Hydrogen Evolution ◽  
Visible Light Irradiation ◽  
Conjugated Polymer ◽  
Narrow Band ◽  
Light Irradiation ◽  
High Hydrogen ◽  
Photocatalytic Hydrogen Evolution ◽  
Hydrogen Evolution Rate

Narrow band gap conjugated polymer photocatalysts containing dithieno[3,2-b:2′,3′-d]thiophene-S,S-dioxide show an attractive photocatalytic hydrogen evolution rate of 16.32 mmol h−1 g−1 under visible light irradiation.

Photocatalytic Properties of α-Bi2O3 Nanoneedle Array Synthesized by Hydrothermal Method

2011 ◽  
Vol 181-182 ◽  
pp. 332-335 ◽  
Author(s):  
H.Y. Wang ◽  
Y.C. Yang ◽  
L. Le ◽  
Y. Liu ◽  
J.H. Wei ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Hydrothermal Method ◽  
Visible Light Irradiation ◽  
Narrow Band ◽  
Light Irradiation ◽  
Nanoneedle Array ◽  
Special Morphology ◽  
Array Structures

Pureα-Bi2O3with nanoneedle array structure was synthesized directly by hydrothermal method. The optic absorption of theα-Bi2O3paricles was cut off at ~483 nm and the band gap of theα-Bi2O3was estimated to be 2.57 eV. The photocatalytic activity of theα-Bi2O3samples was higher than TiO2under a visible light irradiation. As a conclusion, relative narrow band gap ofα-Bi2O3nanoneedle array compared to anatase and the special morphology of nanoneedle array structures may improve the photocatalytic activity in visible light irradiation.

Gold nanoparticles-sensitized wide and narrow band gap TiO2 for visible light applications: a comparative study

2015 ◽  
Vol 39 (6) ◽  
pp. 4708-4715 ◽  
Author(s):  
Sajid Ali Ansari ◽  
Mohammad Mansoob Khan ◽  
Mohd Omaish Ansari ◽  
Moo Hwan Cho
Keyword(s):  
Gold Nanoparticles ◽  
Comparative Study ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Band Gap ◽  
Organic Compounds ◽  
Visible Light Irradiation ◽  
Narrow Band ◽  
Light Irradiation ◽  
Degradation Of Dyes

Photocatalytic degradation of dyes and organic compounds by Au/P-TiO2 and Au/M-TiO2 nanocomposites under visible light irradiation.

Mechanochemical Synthesis, Structural Characterization and Visible Light Photocatalysis of TiO2/ZnFe2O4 Nnanocomposites

2005 ◽  
Vol 900 ◽  
Author(s):  
Sesha S. Srinivasan ◽  
Nikolai Kislov ◽  
Jeremy Wade ◽  
Matthew Smith ◽  
Elias Stefanakos ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Mechanochemical Synthesis ◽  
Narrow Band ◽  
Energy Levels ◽  
High Energy ◽  
Light Irradiation ◽  
Experimental Parameters ◽  
Synthesis Approach

ABSTRACTNanocomposite heterogeneous semiconductors with suitable energy levels (gaps) are exhibiting excellent photocatalytic properties under visible light irradiation. TiO2/ZnFe2O4 has been selected among different alloys because of (i) its low band gap ∼1.9 eV (ii) the nontoxicity of ZnFe2O4 (iii) visible light absorption characteristics of ZnFe2O4 due to its narrow band gap and (iv) not being susceptible to photoanodic corrosion. A mechanochemical synthesis approach using high energy milling is employed to prepare TiO2/ZnFe2O4 under different experimental parameters and conditions. The effects of ball milling and calcination on the photocatalytic behavior of TiO2 and TiO2/ZnFe2O4 have been determined. The as-milled nanocomposite materials are characterized with PXD, SEM and EDS procedures. The photocatalytic activity of TiO2/ZnFe2O4 nanocomposites for the photodegradation of phenol under visible light irradiation has been studied systematically by UV-Vis spectrometer. It is interesting to note a red shift of 0.25 eV in the absorption edge of the ball-milled TiO2 sample when compared to the non ball milled TiO2 photocatalyst.

p-BiOI/n-SnS2 heterojunction flowerlike structure with enhanced visible-light photocatalytic performance

RSC Advances ◽  
2015 ◽  
Vol 5 (20) ◽  
pp. 15469-15478 ◽  
Author(s):  
Tingting Wang ◽  
Hui Meng ◽  
Xiang Yu ◽  
Yizhu Liu ◽  
Hongbin Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Photocatalytic Performance ◽  
Narrow Band ◽  
Wide Band ◽  
Wide Band Gap ◽  
Electron Hole ◽  
Flowerlike Structure ◽  
P Type ◽  
Visible Light Photocatalytic

A flowerlike BiOI/SnS2 p–n junction is prepared. P–n junction is formed by wide-band-gap n-type SnS2 and narrow-band-gap p-type BiOI. The p–n junction lead to improved electron–hole separation and enhancement in photocatalytic performance.

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.

scholarly journals Synthesis, Analysis, and Testing of BiOBr-Bi2WO6Photocatalytic Heterojunction Semiconductors

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangchao Meng ◽  
Zisheng Zhang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Process ◽  
Light Irradiation ◽  
Enhancement Effect ◽  
Electron Hole ◽  
Experimental Conditions ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Photocatalytic Activities

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

High-pressure zinc oxide phase as visible-light-active photocatalyst with narrow band gap

2017 ◽  
Vol 5 (38) ◽  
pp. 20298-20303 ◽  
Author(s):  
Hadi Razavi-Khosroshahi ◽  
Kaveh Edalati ◽  
Ji Wu ◽  
Yuki Nakashima ◽  
Makoto Arita ◽  
...  
Keyword(s):  
High Pressure ◽  
Zinc Oxide ◽  
Visible Light ◽  
Band Gap ◽  
Narrow Band ◽  
Oxide Phase ◽  
Visible Light Active

High-pressure rocksalt ZnO with a band gap of 1.8 eV, which can absorb visible light.

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