scholarly journals Effective Photocatalytic Activity of Sulfate-Modified BiVO4 for the Decomposition of Methylene Blue Under LED Visible Light

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2681 ◽  
Author(s):  
Vinh Huu Nguyen ◽  
Quynh Thi Phuong Bui ◽  
Dai-Viet N. Vo ◽  
Kwon Taek Lim ◽  
Long Giang Bach ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Hydroxyl Radicals ◽  
High Efficiency ◽  
Separation Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Removal Rate ◽  
Gravimetric Analysis ◽  
X Ray

In this study, we investigated sulfate-modified BiVO4 with the high photocatalytic activity synthesized by a sol-gel method in the presence of thiourea, followed by the annealing process at different temperatures. Its structure was characterized by thermal gravimetric analysis (TGA), powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The BiVO4 synthesized in the presence of thiourea and calcined at 600 °C (T-BVO-600) exhibited the highest photocatalytic degradation efficiency of methylene blue (MB) in water; 98.53% MB removal was achieved within 240 min. The reaction mechanisms that affect MB photocatalytic degradation on the T-BVO-600 were investigated via an indirect chemical probe method, using chemical agents to capture the active species produced during the early stages of photocatalysis, including 1,4-benzoquinone (scavenger for O2−), ethylenediaminetetraacetic acid disodium salt (scavenger for h+), and tert-butanol (scavenger for HO•). The results show that holes (h+) and hydroxyl radicals (HO•) are the dominant species of MB decomposition. Photoluminescence (PL) measurement results of terephthalic acid solutions in the presence of BiVO4 samples and BiVO4 powders confirm the involvement of hydroxyl radicals and the separation efficiency of electron-hole pairs in MB photocatalytic degradation. Besides, the T-BVO-600 exhibits good recyclability for MB removal, achieving a removal rate of above 83% after five cycles. The T-BVO-600 has the features of high efficiency and good recyclability for MB photocatalytic degradation. These results provide new insight into the purpose of improving the photocatalytic activity of BiVO4 catalyst.

scholarly journals Synthesis and Characterization of High Efficiency and Stable Spherical Ag3PO4Visible Light Photocatalyst for the Degradation of Methylene Blue Solutions

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Liqin Qin ◽  
Pingfang Tao ◽  
Xiaosong Zhou ◽  
Qi Pang ◽  
Chunjie Liang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Visible Light Photocatalyst ◽  
X Ray

A facile method for the synthesis of Ag3PO4visible light photocatalyst has been developed to improve the photocatalytic activity and stability. The as-prepared samples are investigated by X-ray powder diffraction, scanning electron microscopy, infrared spectroscopy, photoluminescence (PL) spectroscopy, and UV-Vis diffuse reflectance spectroscopy techniques. The results reveal that the prepared Ag3PO4has cube structure with a band gap of 2.26 eV. The as-prepared samples show higher photocatalytic activity for methylene blue (MB) degradation than that of N-TiO2under visible light irradiation.

scholarly journals Fabrication of Titanium Dioxide/Carbon Fiber (TiO2/CF) Composites for Removal of Methylene Blue (MB) from Aqueous Solution with Enhanced Photocatalytic Activity

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hao Cheng ◽  
Wenkang Zhang ◽  
Xinmei Liu ◽  
Tingfan Tang ◽  
Jianhua Xiong
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Carbon Fiber ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Monochromatic Light ◽  
Weight Ratio ◽  
Carbon Fiber Composites ◽  
Simple Method ◽  
X Ray

TiO2 powder was firstly synthesized and carbon fiber was secondly prepared via the carbonization of polyaniline fiber, and TiO2/carbon fiber composites were lastly synthesized via a simple method at room temperature. The prepared samples are evidently investigated by X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, photoluminescence spectrum, and X-ray photoelectron spectroscopy, respectively. Using the monochromatic light of ultraviolet, the photocatalytic activity of the TiO2/CF composites was accurately evaluated with respect to the degradation of an aqueous dye (methylene blue) solution. The relationship between the photocatalytic degradation of methylene blue dye and its ratio, contact time, and the amount of catalyst was studied. The kinetics and mechanisms of degradation were discussed. The results show that TiO2/CF composites have good photocatalytic activity and stability. The TiO2/CF2/1 composite was used in effective photocatalytic degradation of methylene blue, the weight ratio of TiO2 to carbon fiber was 2:1, and the degradation rate was obtaining up to 97.7% of degradation during 120 min of reaction. The photocatalytic stability of TiO2/CF composites was dependent on the stability of their structure. After 5 repeated uses, the composite TiO2/CF2/1 still exhibited rather high activity toward the degradation of methylene blue, where the decolorization efficiency of methylene blue achieved 92% and the loss of activity was negligible. Based on radical trapping experiments, the mechanism of TiO2/CF composites on photocatalytic degradation of methylene blue is proposed, which could explain the enhanced photocatalytic activity of the composites better. Superoxide radicals, photogenerated holes, and photogenerated electrons were the main active substances for methylene blue degradation.

Photocatalytic Degradation of Methylene Blue over Co-Ag3VO4 under Visible Light Irradiation

2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Light Irradiation ◽  
Experimental Conditions ◽  
X Ray

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.

scholarly journals High efficient photocatalytic activity of Zn-Al-Ti layered double hydroxides nanocomposite

2018 ◽  
Vol 149 ◽  
pp. 01087 ◽  
Author(s):  
F. Amor ◽  
A. Diouri ◽  
I. Ellouzi ◽  
F. Ouanji ◽  
M. Kacimi
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Uv Irradiation ◽  
Layered Double Hydroxides ◽  
Removal Rate ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
High Efficient ◽  
Double Hydroxides

This work establishes a simple method for synthesising layered double hydroxides (LDHs) powders with coprecipitation. The characteristics of the samples were investigated y X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer UV–Vis (DRS). Non-uniform distribution was shown for LDHs samples by SEM. Photocatalytic efficiencies were tested using methylene blue (MB) dye as a model contaminant under UV irradiation. In particular, Zn–Al-Ti LDH exhibited an excellent performance towards MB degradation compared with commercial TiO2 nanoparticles. Methylene blue removal percentage was reached at almost 100%, whereas commercial TiO2 reached a removal rate of only 66% under the same conditions within 20 min. The aim of the current work is to prepare Zn-Al-Ti layered double hydroxides nanocomposite and to evaluate their photocatalytic activity in the removal of methylene blue under UV irradiation.

scholarly journals Zirconia nanoparticle-modified graphitic carbon nitride nanosheets for effective photocatalytic degradation of 4-nitrophenol in water

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Mohanna Zarei ◽  
Jamil Bahrami ◽  
Mohammad Zarei
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Carbon Nitride ◽  
Diffuse Reflectance Spectroscopy ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconia Nanoparticle ◽  
Carbon Nitride Nanosheets

Abstract Zirconia (ZrO2)-modified graphitic carbon nitride (g-C3N4) nanocomposite was used for effective photodegradation of 4-nitrophenol (4-NP) in water. The ZrO2 nanoparticles, g-C3N4 nanosheets, and ZrO2/g-C3N4 nanocomposite were well characterized by including N2 adsorption, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy methods. ZrO2/g-C3N4 nanocomposites were formed at room temperature using sonication and used for effective for photodegradation of 4-NP under irradiation with visible light. The nanocomposite samples resulted in a significant increase in photocatalytic activity compared with single-component samples of g-C3N4. In particular, the ZrO2/g-C3N4 nanocomposite exhibited the significant increase in the photocatalytic activity. The ZrO2/g-C3N4 nanocomposite showed an excellent catalytic activity toward the reduction of 4-NP in aqueous medium. Further, ZrO2/g-C3N4 nanocomposite can be reused several times for photocatalytic degradation as well as for 4-NP adsorption.

Photocatalytic decolourization of methylene blue using [Zn-Al] layered double hydroxides synthesized at different molar cationic ratios

Clay Minerals ◽  
2017 ◽  
Vol 52 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Kaouther Abderrazek ◽  
Najoua Frini Srasra ◽  
Ezzeddine Srasra
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Layered Double Hydroxides ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Molar Ratios ◽  
Constant Ph ◽  
Double Hydroxides

Abstract[Zn-Al] layered double hydroxides (LDH) with cationic molar ratios of R = Zn/Al 1–5 were synthesized by the coprecipitation method at constant pH = 10. The samples synthesized and their derived forms obtained after calcination at 500°C and at 900°C (denoted Zn-Al-R, Zn-Al-R-500 and Zn-Al-R-900, respectively), were characterized by X-ray diffraction (XRD), inductively coupled plasmamass spectrometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, diffuse reflectance spectroscopy and nitrogen physisorption at −196°C. The XRD study showed: (1) the presence of accessory ZnO with the LDH in samples synthesized with R ≥ 3; and (2) the lamellar structure was destroyed at 500°C which made room for a poorly ordered ZnO phase, while calcination at 900°C yielded well crystallized ZnO and ZnAl2O4. The photocatalytic activity of the calcined and the unheated samples was evaluated for the decolourization of methylene blue. The photocatalytic activity was dependent on the cationic ratio R and on the calcination temperature. The sample Zn-Al-3 displayed maximum photocatalytic activity. Calcination at 500 and 900°C improved the photocatalytic activity of LDH synthesized at R = 1 and 2.

scholarly journals Synthesis of BiSI/Ag2CO3 Composite Material for Photocatalytic Degradation of Rhodamine B under Visible Light

2021 ◽  
Author(s):  
Rui Zhang ◽  
ziyin chen ◽  
Chen Zhao ◽  
Kunlin Zeng ◽  
Lu Cai ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Photocatalytic Performance ◽  
Electrochemical Impedance ◽  
Diffuse Reflectance Spectroscopy ◽  
Mass Ratio ◽  
X Ray ◽  
Visible Light Driven

Abstract A novel binary BiSI/Ag2CO3 photocatalyst with excellent visible light-driven photocatalytic performance was prepared. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the samples were evaluated by photocatalytic degradation of rhodamine B(RhB) under the irradiation of visible light. The results showed that the BiSI improves the photocatalytic activity of BiSI/Ag2CO3. Moreover, when the mass ratio of BiSI in BiSI/Ag2CO3 composites was 40%, the as-prepared BiSI/Ag2CO3 composite exhibited the best photocatalytic activity for degrading RhB. Finally, the possible mechanism for photodegradation over the BiSI/Ag2CO3 composites is also proposed.

scholarly journals Enhanced Visible Light Photocatalytic Degradation of Methylene Blue by CdS-ZnS-BiPO4 Nanocomposites Prepared by a Solvent-Assisted Heating Method

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1095
Author(s):  
Hsin-Chan Tsai ◽  
Yu-Hui Peng ◽  
Po-Yu Wen ◽  
Tsunghsueh Wu ◽  
Yang-Wei Lin
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Separation Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Pond Water ◽  
Molar Ratio ◽  
Cds Nanoparticles ◽  
Heating Method ◽  
Water Matrix

In this study, a ternary CdS-ZnS-BiPO4 nanocomposite, synthesized by a solvent-assisted heating method, demonstrated the highest visible light-induced photocatalysis towards the degradation of methylene blue (MB) when comparing with BiPO4, CdS-BiPO4, and ZnS-BiPO4. Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) were used to characterize the prepared nanocomposites. From UV-DRS results, the energy band gap of the prepared BiPO4 structures was 4.51 eV. When CdS nanoparticles were deposited on BiPO4 surface by a solvent-assisted heating method, the prepared nanocomposites exhibited visible light-responsive photocatalytic degradation toward MB (20 ppm). At a molar ratio of Cd to Zn as 1:7, the prepared CdS-ZnS-BiPO4 nanocomposites exhibited the best photocatalytic activity in degrading 95% of MB dyes, out-performing pure BiPO4, CdS-BiPO4, and ZnS-BiPO4 due to its enhanced charge separation efficiency and the lowered carrier recombination from the efficient p-n junction of unprecedented ternary composites. The investigations on mechanism conclude that the major reactive species responsible for MB degradation are holes and oxygen radicals. For practicality, the degradation efficiency for different dyestuff (Fast Green FCF, Rhodamine 6G, Acid Blue 1, methyl orange, and methyl red) degradation in the different water matrix samples (pond water, seawater, and lake water) by the prepared CdS-ZnS-BiPO4 nanocomposites was evaluated.

Preparation of BiXY(2-X)O3 and its Photocatalytic Degradation of Molasses Fermentation Wastewater under Visible-Light Irradiation

2011 ◽  
Vol 287-290 ◽  
pp. 1640-1645 ◽  
Author(s):  
Min Guang Fan ◽  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Tong Ming Su
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Oxygen Species ◽  
Light Irradiation ◽  
X Ray

A series of BixY(2-x)O3photocatalysts were successfully prepared by a solid-state reaction and were subsequently characterized by powder X-ray diffraction, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The UV-vis diffuse reflectance spectra revealed that the BixY(2-x)O3samples absorbed light in the visible-light range (400-800 nm). The XPS results indicated that active oxygen species were generated on the Bi1.8Y0.2O3surface, which displayed a higher photocatalytic activity. When using photocatalytic degradation molasses fermentation wastewater as a model reaction, the Bi1.8Y0.2O3showed higher photocatalytic activity in comparison to Bi0.2Y1.8O3under visible-light irradiation.

The Influence of ZnO Components on the Photocatalytic Activity of Fe3O4-CuO-ZnO Nanocomposites

2015 ◽  
Vol 1123 ◽  
pp. 227-232 ◽  
Author(s):  
Iqriah Kalim Susanto ◽  
Ardiansyah Taufik ◽  
Rosari Saleh
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible

Nanocomposite Fe3O4-CuO-ZnO with different molar ratio of Fe3O4:CuO:ZnO were synthesized using sol-gel method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope, UV-visible diffuse reflectance spectroscopy and vibrating sample magnetometer. The characterization results manifested that the combination of Fe3O4, CuO and ZnO nanoparticles was successful. The photocatalytic activity of nanocomposite with the molar ratio of 1:1:5 was more effective in the degradation of methylene blue under UV light irradiation than pure Fe3O4, CuO, ZnO. The role of photoactive species involved in the photocatalytic reaction was studied and found that holes play the most important role in photodegradation of methylene blue.

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