Effects of Synthesis Conditions on the Crystalline Phases and Photocatalytic Activities of Silver Vanadates via Hydrothermal Method

2009 ◽  
Vol 1171 ◽  
Author(s):  
Chao-Ming Huang ◽  
Guan T. Pan ◽  
Lung C. Chen ◽  
C.K. Thomas Yang ◽  
Wen S. Chang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
Synthesis Method ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Synthesis Conditions ◽  
Vis Spectroscopy ◽  
Visible Light Driven

AbstractVisible-light-driven Ag3VO4 photocatalysts were successfully synthesized using low-temperature hydrothermal synthesis method. Under various hydrothermal conditions, the structures of silver vanadates were tuned by manipulating the hydrothermal time and the ratio of silver to vanadium. X-ray diffraction (XRD) results reveal that the powders prepared in a stoichiometric ratio consisted of pure α-Ag3VO4 or mixed phases of Ag4V2O7 and α-Ag3VO4. With increasing the Ag-to-V mole ratio to 6:1, the resulting samples were identified as pure monoclinic structure α-Ag3VO4. UV-vis spectroscopy indicated that silver vanadate particles had strong visible light absorption with associated band gaps in the range of 2.2-2.5 eV. The sample synthesized in the excess silver exhibited higher photocatalytic activity than that synthesized in a stoichiometric ratio. The powder synthesized at silver-rich at 140℃ for 4 h (SHT4) exhibited the highest photocatalytic activity among all samples. The reactivity of SHT4 (surface area, 3.52 m2 g-1) on the decomposition of gaseous benzene was about 16 times higher than that of P25 (surface area, 49.04 m2 g-1) under visible light irradiation. A well developed crystallinity of Ag3VO4 of SHT 4 was considered to enhance the photocatalytic efficiency.

Photocatalytic Activity of CuO/ZnO Heterostructure Nanocrystals under UV-Visible Light Irradiation

2014 ◽  
Vol 787 ◽  
pp. 35-40 ◽  
Author(s):  
Xiao Yan Zhou ◽  
Peng Wei Zhou ◽  
Hao Guo ◽  
Bo Yang ◽  
Ru Fei Ren
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Cuo Nanoparticles ◽  
Light Irradiation ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Uv Visible

The p-n junction photocatalysts, p-CuO (at. 0-25%)/n-ZnO nanocomposite were prepared through hydrothermal method without using any organic solvent or surfactant. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy, and UV-vis spectroscopy. The results demonstrated that the CuO/ZnO nanocomposite presented a two-dimensional morphology composed of sheet-like ZnO nanostructures adorned with CuO nanoparticles. The photocatalytic activity of CuO/ZnO with different Cu/Zn molar rations and pure ZnO synthesized by the identical synthetic route were evaluated by degrading methylene blue (MB) dye under UV-visible light irradiation. The CuO/ZnO with Cu/Zn molar ratio of 4% exhibits the highest photocatalytic activity compared that of the other photocatalysts under the identical conditions. It is mainly attributed to the increased charge separation rate in the nanocomposite and the extended photo-responding range.

scholarly journals Structural and optical properties of AgCl-sensitized TiO2 (TiO2 @AgCl) prepared by a reflux technique under alkaline condition

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 190-196 ◽  
Author(s):  
V. A. Mu’izayanti ◽  
H. Sutrisno
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Alkaline Condition ◽  
Visible Light Region ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Light Region ◽  
Vis Spectroscopy ◽  
Xrd Patterns ◽  
Tio2 Rutile

Abstract The AgCl-sensitized TiO2 (TiO2@AgCl) has been prepared from the precursor of TiO2-rutile type which on its surface adsorb chloride anion (Cl-) and various amounts of silver using AgNO3 as starting material: AgNO3/(AgNO3+TiO2) mass ratio of 0.00, 1.14, 3.25, 6.38 and 10.32%. Reflux under alkaline condition was the employed technique. All samples were characterized by X-ray diffraction (XRD) and diffuse reflectance UV-vis spectroscopy. The sample without the addition of AgNO3 was analyzed by scanning electron microscope and surface area analyzer. The morphology of the sample showed a distribution of microspheres of approximately 0.5 to 1.0 µm and the specific surface area was 68 m2/g. XRD patterns indicated that the sample without the addition of AgNO3 contained two types of TiO2: rutile (major) and anatase (minor), whereas the samples with the addition of AgNO3 consisted of one phase of AgCl and two types of TiO2: rutile and anatase. The bandgaps of the samples were in the range of 2.97 to 3.24 eV, which were very close to the bandgap of intrinsic TiO2 powder. The presence of 0.8, 2.6 and 4.4 wt% of AgCl in each sample resulted in an additional bandgap in visible light region of 1.90, 1.94 and 2.26 eV, respectively, whereas the presence of 9.4 wt% of AgCl in the sample resulted in two bandgaps in visible light region of 1.98 and 1.88 eV.

Effect of Iron (III)-Doping on the Photocatalytic Activity of Titanium Dioxide Catalysts for Methylene Blue Degradation

2011 ◽  
Vol 117-119 ◽  
pp. 1088-1091
Author(s):  
Wen Churng Lin ◽  
Rui Liu ◽  
Wein Duo Yang
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Effective Means ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Surface Areas ◽  
Bet Specific Surface Area ◽  
Vis Spectroscopy

Iron-doped TiO2 photocatalyst powders were prepared by the sol–gel method and characterized by Brunauer–Emmett–Teller (BET)-specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Ultraviolet–Visible (UV-Vis) spectroscopy. Fe3+ doping in the TiO2 decreases the crystal grain size, increases the specific surface areas of powders, extends the absorption to visible light regions (400~500 nm), and lowers the photocatalytic activity for methylene blue (MB) degradation under UV irradiation. The photocatalytic degradation of MB in water was investigated as a function of the Fe3+ content in TiO2. It was found that under the irradiation of visible light, a small amount of Fe3+ dopant in TiO22 powders could obviously enhance the photocatalytic activity. When the Fe3+ content was in the range of 0.03–0.1 mol%, the photocatalytic activity of the samples was higher than that of undoped TiO2. Appropriate content of Fe-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation.

The Effects of Solvents on the Solvothermal Synthesis of BiVO4 Photocatalyst Powders

2015 ◽  
Vol 659 ◽  
pp. 154-158
Author(s):  
N. Thanomsri ◽  
C. Mongkolkachit ◽  
T. Sato ◽  
X. Wu ◽  
Pornapa Sujaridworakun
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
X Ray Diffraction ◽  
Photo Degradation ◽  
X Ray ◽  
Structure Surface ◽  
Xrd Patterns ◽  
Visible Light Photocatalytic

In this study, the effects of different solvents such as ethanol, ethylene glycol, glycerol on the preparation of BiVO4 via solvothermal process, and the influent of calcination heat treatment were studied. The crystal structure, surface area, morphology and optical properties of the obtained BiVO4 particles were investigated by means of X-ray Diffraction (XRD), Brunauer Emmett Teller method (BET), Scanning electron microscope (SEM) and UV-Vis reflectance spectroscopy (UV-Vis DRS), respectively. XRD patterns reveal that all of the obtained BiVO4 samples prepared by solvothermal at 130°C for 4 h have monoclinic structure. The UV-Vis DRS demonstrates that the band gaps of prepared BiVO4 are about 2.38-2.40 eV. The photocatalytic activity was evaluated by photo-degradation of rhodamine B (Rh B) solution under visible light irradiation (λ>420 nm). As the results, the BiVO4 prepared by using ethanol having high crystallinity and surface area showed the highest visible light photocatalytic activity compared to using glycerol and ethylene glycerol, respectively. Furthermore, the photocatalytic activity of BiVO4 prepared by using ethylene glycerol and glycerol could be enhanced by calcination heat treatment at 500°C for 2 h.

Novel core–shell structured BiVO4 hollow spheres with an ultra-high surface area as visible-light-driven catalyst

CrystEngComm ◽  
2014 ◽  
Vol 16 (27) ◽  
pp. 6059-6065 ◽  
Author(s):  
Yang Lu ◽  
Yong-Song Luo ◽  
Hong-Mei Xiao ◽  
Shao-Yun Fu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
High Surface ◽  
Hollow Spheres ◽  
High Surface Area ◽  
Core Shell ◽  
Hydrothermal Route ◽  
Excellent Photocatalytic Activity ◽  
Visible Light Driven

Novel core–shell-structured BiVO4 hollow spheres synthesized via a simple hydrothermal route exhibit an excellent photocatalytic activity.

Enhancement of visible light photocatalytic activity of tantalum oxynitride and tantalum nitride by coupling with bismuth oxide; an example of composite photocatalysis

2015 ◽  
Vol 1738 ◽  
Author(s):  
Shiba P Adhikari ◽  
Lifeng Zhang ◽  
Michael Gross ◽  
Abdou Lachgar
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Bismuth Oxide ◽  
Synthesis Method ◽  
Visible Region ◽  
Solution Chemistry ◽  
Tantalum Nitride ◽  
Electromagnetic Spectrum ◽  
Vis Spectroscopy ◽  
Photocatalytic Activities

ABSTRACTComposite photocatalysts comprised of two semiconducting oxides, with suitable band gaps and band positions, have been reported as an effective approach to enhance photocatalytic activity in the visible region of the electromagnetic spectrum. Here, we report the synthesis, characterization, and photocatalytic evaluations of semiconducting composites made by combing bismuth oxide with either tantalum oxynitride or tantalum nitride. Visible light active composites were synthesized using solution chemistry synthesis method. The composites were characterized by powder X- ray diffraction (PXRD), diffuse reflectance UV-Vis spectroscopy, and photoluminescence (PL). Their photocatalytic activities were evaluated for generation of hydrogen from an aqueous methanol solution under visible light irradiation (λ≥ 420 nm). The as-prepared composite catalysts are found to have longer photogenerated charge-carrier life time, resulting in enhanced photocatalytic activities.

scholarly journals Three-Dimensional Zn0.5Cd0.5S/Reduced Graphene Oxide Hybrid Aerogel: Facile Synthesis and the Visible-Light-Driven Photocatalytic Property for Reduction of Cr(VI) in Water

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Xiao ◽  
Wenjie Zhou ◽  
Yanhua Zhang ◽  
Liangliang Tian ◽  
Hongdong Liu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Three Dimensional ◽  
Reduced Graphene ◽  
Visible Light Driven

A series of three-dimensional ZnxCd1-xS/reduced graphene oxide (ZnxCd1-xS/RGO) hybrid aerogels was successfully synthesized based on a one-pot hydrothermal approach, which were subsequently used as visible-light-driven photocatalysts for photoreduction of Cr(VI) in water. Over 95% of Cr(VI) was photoreduced by Zn0.5Cd0.5S/RGO aerogel material within 140 min, and such photocatalytic performance was superior to that of other ZnxCd1-xS/RGO aerogel materials (x≠0.5) and bare Zn0.5Cd0.5S. It was assumed that the enhanced photocatalytic activity of Zn0.5Cd0.5S/RGO aerogel was attributed to its high specific surface area and the preferable synergetic catalytic effect between Zn0.5Cd0.5S and RGO. Besides, Zn0.5Cd0.5S/RGO aerogel materials were robust and durable enough so that they could be reused several times with merely limited loss of photocatalytic activity. The chemical composition, phase, structure, and morphology of Zn0.5Cd0.5S/RGO aerogel material were carefully examined by a number of techniques like XRD, SEM, TEM, BET, Raman characterizations, and so on. It was found that Zn0.5Cd0.5S/RGO aerogel possessed hierarchically porous architecture with the specific surface area as high as 260.8 m2 g−1. The Zn0.5Cd0.5S component incorporated in Zn0.5Cd0.5S/RGO aerogel existed in the form of solid solution nanoparticles, which were uniformly distributed in the RGO matrix.

scholarly journals Synthesis of Tungsten Oxide as Visible Light-Driven Photocatalyst for Removal of Salicylic Acid

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Leny Yuliati ◽  
Mazalan Maisarah ◽  
Hendrik O. Lintang
Keyword(s):  
Photocatalytic Activity ◽  
Salicylic Acid ◽  
Visible Light ◽  
Tungsten Oxide ◽  
High Photocatalytic Activity ◽  
X Ray Diffraction ◽  
Calcination Temperatures ◽  
Visible Light Driven ◽  
Loading Amount ◽  
Mesoporous Carbon Nitride

In the present study, tungsten oxide (WO3) was prepared using mesoporous carbon nitride (m-C3N4) as a template. Based on the results obtained from X-ray diffraction (XRD) and diffuse reflectance (DR) UV-Visible spectroscopy, it was confirmed that WO3 can be successfully prepared at all investigated calcination temperatures, even at low temperature of 200°C. It was found that the WO3 prepared at 700°C using m-C3N4 showed higher photocatalytic activity than the WO3 commercial for salicylic acid removal under visible light irradiation. With the optimum loading amount of platinum as cocatalyst, 80.6% of salicylic acid removal was obtained on the prepared WO3. It was suggested that the small particle size and the high crystallinity of the prepared WO3 played important role in giving high photocatalytic activity.

Preparation and Photocatalytic Activity of TiO2/FeOOH Nanocomposite

2012 ◽  
Vol 535-537 ◽  
pp. 219-222
Author(s):  
Dan Chen ◽  
Su Juan Hu ◽  
Guo Hua Li
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Property ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Preparation Temperature ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Phase Pure ◽  
Electron Hole Pair

TiO2/FeOOH nanocomposite was fabricated by a hydrolysis-precipitation approach, using TiCl4 as precursor and FeOOH as support. The crystal phase, diameter and morphology of the sample particle were characterized by X-ray diffraction, transmission electron microscope. The results show that the samples are composed of goethite and rutile. The morphology and diameter of rutile particle, the weight percentages of goethite and rutile, and the microstructure of the samples are related to its preparing temperature and molar ratio of Fe/Ti. The photo-absorption properties of the samples and support were measured by an UV-vis spectroscopy. The results show that the absorption ability of the nanocomposite for visible light is well than that of phase pure rutile. The photocatalytic activity of the nanocomposite as prepared was estimated by degradation of methyl orange (MO) under UV or visible light in an aqueous solution at 303 K. The results indicate that the photocatalytic degradation activity of the nanocomposite for MO is higher than that of phase pure rutile, and the photocatalytic property of the sample is related to its molar ratio of Fe/Ti and preparation temperature. This can be attributed to the microstructure of the nanocomposite, which can improve solar utilization and reduce the recombination rate of solar induced electron-hole pair. This implies that a synergistic effect exists between titania and goethite in the nanocomposite.

Synthesis of an Ag3PO4/AlPO4 composites for enhanced visible light-driven photocatalytic activity

2020 ◽  
Vol 10 (8) ◽  
pp. 1284-1291
Author(s):  
Yanlin Zhang ◽  
Fuzhong Gong ◽  
Yanlin Li ◽  
Sunqi Liao
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Precipitation Method ◽  
Molar Ratios ◽  
Homogeneous Precipitation Method ◽  
Degradation Of Dyes ◽  
Vis Spectroscopy ◽  
Bet Method ◽  
Visible Light Driven

Novel non-porous Ag3PO4/AlPO4 composites with a stick shape were synthesized using the homogeneous precipitation method and characterized by XRD, FESEM, XPS, UV-vis spectroscopy and BET method. The photocatalytic performance was evaluated by degradation of MB and MO upon irradiation with visible light. Results indicate that when the molar ratios of Ag3PO4 to AlPO4 are 6:4 or higher, remarkable increases in photocatalytic activity were observed compared with the pure Ag3PO4 powder. The possible mechanism of photocatalytic degradation of dyes by Ag3PO4/AlPO4 composites was proposed.

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