scholarly journals Photodegradation of naphthalene over Fe 3 O 4 under visible light irradiation

2019 ◽  
Vol 6 (1) ◽  
pp. 181779
Author(s):  
Jiawei Zhang ◽  
Shanshan Fan ◽  
Bin Lu ◽  
Qinghai Cai ◽  
Jingxiang Zhao ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Products ◽  
Magnetic Measurement ◽  
Average Diameter ◽  
Degradation Pathway ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Naoh Solution ◽  
Co Precipitation

Using FeCl 3 and FeSO 4 as precursors, Fe 3 O 4 were prepared by co-precipitation method via FeCl 3 and FeSO 4 aqueous solutions successively added to NaOH solution. The sample was proved by X-ray powder diffraction, transmission electron microscope, ultraviolet–visible spectrophotometry and magnetic measurement. The results showed that the prepared Fe 3 O 4 material was composed of an average diameter of about 15 nm particles and nano rods with well-crystallized magnetite and stronger superparamagnetic, getting a saturation magnetization of 49.5 emu g −1 . This Fe 3 O 4 material was found to be an effective catalyst for photodegradation of naphthalene with or without H 2 O 2 under visible light irradiation, getting 81.1% and 74.3% degradation rate in these two cases, respectively. The degradation pathway in the absence and presence of H 2 O 2 was analysed via measurement of the distribution of degradation products by GC-MS and adsorption of reactants on the surface of the catalyst by in situ DRIFTS spectra.

scholarly journals High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

2014 ◽  
Vol 5 ◽  
pp. 587-595 ◽  
Author(s):  
Leny Yuliati ◽  
Melody Kimi ◽  
Mustaffa Shamsuddin
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Ag Doping ◽  
Light Region ◽  
Co Precipitation

Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation. Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation. Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst.

Synthesis of Bi2O3/Ag3Po4 Composites and their Photocatalytic Activities under Visible Light Irradiation

2015 ◽  
Vol 1112 ◽  
pp. 163-167 ◽  
Author(s):  
Uyi Sulaeman ◽  
Estri Yunari ◽  
Ponco Iswanto ◽  
Shu Yin ◽  
Tsugio Sato
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Body Centered Cubic ◽  
Bet Specific Surface Area ◽  
Photocatalytic Activities ◽  
Co Precipitation ◽  
Rhodamin B

The Bi2O3/Ag3PO4 composites consisting of the monoclinic α-Bi2O3 and body-centered cubic Ag3PO4 were successfully synthesized by grinding Ag3PO4 and Bi2O3 mixtures in ethanol using an agate mortar, followed by calcination at 500°C for 5 hours, where the Ag3PO4 was synthesized by co-precipitation method using AgNO3 and NaH2PO4.2H2O as starting materials. The Bi2O3 content in the composite materials changed from 5 to 25 mol.%. The composites were characterized using XRD, DRS and BET specific surface area. The photocatalytic activities were evaluated using Rhodamin B degradation under visible light irradiation of blue LED (λ = 445 nm). The highest photocatalytic activities could be obtained at 5 mol.% Bi2O3 in Bi2O3/Ag3PO4 composite. The enhanced photocatalytic activity could be attributed to the effective separation of hole (h+) and electron (e-) pairs in the Bi2O3/Ag3PO4 composite.

scholarly journals Improved ciprofloxacin removal by a Fe(VI)-Fe3O4/graphene system under visible light irradiation

2018 ◽  
Vol 2017 (2) ◽  
pp. 527-533 ◽  
Author(s):  
Shunping Fang ◽  
Zhengwei Zhou ◽  
Jinjuan Xue ◽  
Guangyu He ◽  
Haiqun Chen
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
High Performance ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
Determining Factors ◽  
Co Precipitation

Abstract In this paper, Fe3O4/graphene (Fe3O4/GE) nanocomposites were prepared by a co-precipitation method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). The composites were used in combination with Fe(VI) to construct a Fe(VI)-Fe3O4/GE system in order to degrade ciprofloxacin (CIP) in simulated water samples. The photocatalytic properties of Fe(VI)-Fe3O4/GE were evaluated under visible light irradiation. The concentration of CIP in solution was detected by high performance liquid chromatography (HPLC). A series of results showed that Fe(VI), as a good electron capture agent, could significantly improve the treatment performance. Major determining factors during CIP degradation were also investigated, in which solution pH of 9, Fe(VI) to Fe3O4/GE dosage ratio of 1:25 and GE content in the Fe3O4/GE nanocomposites of 10 wt% were found to be the best experimental conditions. The results demonstrated that the Fe(VI)-Fe3O4/GE system could offer an alternative process in water treatment in addition to the current Fe(VI)-UV/TiO2 process.

scholarly journals Photocatalytic Hydrogen Production from Glycerol Aqueous Solution Using Cu-Doped ZnO under Visible Light Irradiation

2019 ◽  
Vol 9 (13) ◽  
pp. 2741 ◽  
Author(s):  
Vincenzo Vaiano ◽  
Giuseppina Iervolino
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Noble Metals ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Glycerol Solution ◽  
Glycerol Concentration ◽  
Photocatalytic Hydrogen Production ◽  
Doped Zno

Cu-doped ZnO photocatalysts at different Cu loadings were prepared by a precipitation method. The presence of Cu in the ZnO crystal lattice led to significant enhancement in photocatalytic activity for H2 production from an aqueous glycerol solution under visible light irradiation. The best Cu loading was found to be 1.08 mol %, which allowed achieving hydrogen production equal to 2600 μmol/L with an aqueous glycerol solution at 5 wt % initial concentration, the photocatalyst dosage equal to 1.5 g/L, and at the spontaneous pH of the solution (pH = 6). The hydrogen production rate was increased to about 4770 μmol/L by increasing the initial glycerol concentration up to 10 wt %. The obtained results evidenced that the optimized Cu-doped ZnO could be considered a suitable visible-light-active photocatalyst to be used in photocatalytic hydrogen production without the presence of noble metals in sample formulation.

scholarly journals Visible Light Responsive Strontium Carbonate Catalyst Derived from Solvothermal Synthesis

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1069
Author(s):  
Pornnaphat Wichannananon ◽  
Thawanrat Kobkeatthawin ◽  
Siwaporn Meejoo Smith
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Products ◽  
Reaction Pathway ◽  
Direct Injection ◽  
Radical Scavenging ◽  
Strontium Carbonate ◽  
Light Irradiation ◽  
Light Illumination ◽  
Strontium Hydroxide

A single crystalline phase of strontium carbonate (SrCO3) was successfully obtained from solvothermal treatments of hydrated strontium hydroxide in ethanol (EtOH) at 100 °C for 2 h, using specific Sr:EtOH mole ratios of 1:18 or 1:23. Other solvothermal treatment times (0.5, 1.0 and 3 h), temperatures (80 and 150 °C) and different Sr:EtOH mole ratios (1:13 and 1:27) led to formation of mixed phases of Sr-containing products, SrCO3 and Sr(OH)2 xH2O. The obtained products (denoted as 1:18 SrCO3 and 1:23 SrCO3), containing a single phase of SrCO3, were further characterized in comparison with commercial SrCO3, and each SrCO3 material was employed as a photocatalyst for the degradation of methylene blue (MB) in water under visible light irradiation. Only the 1:23 SrCO3 sample is visible light responsive (Eg = 2.62 eV), possibly due to the presence of ethanol in the structure, as detected by thermogravimetric analysis. On the other hand, the band gap of 1:18 SrCO3 and commercial SrCO3 are 4.63 and 3.25 eV, respectively, and both samples are UV responsive. The highest decolourisation efficiency of MB solutions was achieved using the 1:23 SrCO3 catalyst, likely due to its narrow bandgap. The variation in colour removal results in the dark and under visible light irradiation, with radical scavenging tests, suggests that the high decolourisation efficiency was mainly due to a generated hydroxyl-radical-related reaction pathway. Possible degradation products from MB oxidation under visible light illumination in the presence of SrCO3 are aromatic sulfonic acids, dimethylamine and phenol, as implied by MS direct injection measurements. Key findings from this work could give more insight into alternative synthesis routes to tailor the bandgap of SrCO3 materials and possible further development of cocatalysts and composites for environmental applications.

Construction of ZnxCd1−xS/CeO2 composites for enhanced photocatalytic activity and stability by chemical precipitation method

2021 ◽  
pp. 2150334
Author(s):  
Yi-Feng Chai ◽  
Zhong-Hua Zhu ◽  
Ming-Wei Liu ◽  
Jing Zeng ◽  
Gui-Fang Huang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Uv Light ◽  
Chemical Precipitation ◽  
Charge Carriers ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Uv Light Irradiation

Development photoinduced photocatalysts is a significant approach to improve photocatalytic activity and stability. Herein, we successfully prepared Zn[Formula: see text]Cd[Formula: see text]S/CeO2 composites by a facile method. It is found that the Zn[Formula: see text]Cd[Formula: see text]S/CeO2 composites show significant enhancement in photocatalytic activity for methyl orange (MO) degradation under visible and UV light irradiation. The degradation efficiency reaches up to 3.7 times higher than that of pure CeO2 under visible light irradiation. Moreover, the Zn[Formula: see text]Cd[Formula: see text]S/CeO2 samples have almost no loss of photocatalytic activity after five recycles, indicating good photocatalytic stability of the samples. The attractive photocatalytic activity of the Zn[Formula: see text]Cd[Formula: see text]S/CeO2 samples could be attributed to the robust charge carriers transfer and separation.

scholarly journals Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag2S/BiFeO3 Heterojunction Composites under Visible-Light Irradiation

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 399 ◽  
Author(s):  
Lijing Di ◽  
Hua Yang ◽  
Tao Xian ◽  
Xueqin Liu ◽  
Xiujuan Chen
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Dye Degradation ◽  
Synergistic Effects ◽  
Active Species ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Photoexcited Electron ◽  
Catalytic Mechanisms ◽  
Ag2s Nanoparticles

Z-scheme Ag2S/BiFeO3 heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag2S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO3 particles (500–800 nm) to form Ag2S/BiFeO3 heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag2S/BiFeO3 heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag2S/BiFeO3 composites exhibit much improved photocatalytic activities when compared with bare Ag2S and BiFeO3. The optimum composite sample was observed to be 15% Ag2S/BiFeO3 with an Ag2S mass fraction of 15%. Furthermore, the addition of H2O2 can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag2S/BiFeO3 composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag2S/BiFeO3 composites were proposed and discussed.

Enhanced Photocatalytic Activity by Silver-Modified Bismuth Vanadate

2017 ◽  
Vol 757 ◽  
pp. 88-92
Author(s):  
Cheewita Suwanchawalit ◽  
Kamonchanok Roongraung ◽  
Supat Buddee ◽  
Sumpun Wongnawa ◽  
Avinash Patil
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Visible Region ◽  
Bismuth Vanadate ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Blue Dye ◽  
Vis Spectroscopy

Silver-modified bismuth vanadate (Ag-BiVO4) photocatalysts were easily prepared via the co-precipitation method. The effects of silver contents on the chemical properties of BiVO4 were evaluated. The prepared Ag-BiVO4 samples were characterized by several techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), and diffused reflectance UV-Vis spectroscopy (DRS). The mixed phase of monoclinic scheetlite structure and characteristic peaks of silver particles were found. Silver contents strongly affect the morphology of the prepared Ag-BiVO4 samples. DRS spectra revealed that the synthesized Ag-BiVO4 samples exhibited strong absorption in the visible region. The absorption in the visible zone is responsible for the high photocatalytic activity of Ag-BiVO4 under visible light irradiation. The photocatalytic degradation of methylene blue under visible light irradiation was studied using the BiVO4 as photocatalysts. The photocatalytic results reveal that the prepared Ag-BiVO4 samples could degrade the methylene blue dye.

scholarly journals Photocatalytic degradation of organic dye and tetracycline by ternary Ag2O/AgBr–CeO2 photocatalyst under visible-light irradiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fu Su ◽  
Pengpeng Li ◽  
Jianshu Huang ◽  
Meijuan Gu ◽  
Zhiying Liu ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Ag Nanoparticles ◽  
Photocatalytic Performance ◽  
Analytical Techniques ◽  
Organic Dye ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Initial Capacity

AbstractIn this work, CeO2 nanosheets decorated with Ag2O and AgBr are successfully fabricated via a simple sediment-precipitation method. The as-prepared ternary Ag2O/AgBr–CeO2 composite with double Z-scheme construction was analyzed by various analytical techniques. Ag nanoparticles (NPs) used as the electron medium could reduce the recombination of photoelectrons and holes, thus leading to the improvement of photocatalytic performance of these catalysts. Due to the unique structure and composite advantages, the optimal Ag2O/AgBr–CeO2 photocatalysts exhibit the superior tetracycline (TC) degradation efficiency of 93.23% and favorable stability with near-initial capacity under visible light irradiation. This ternary Z-scheme structure materials will be the well-promising photocatalysts or the purification of antibiotic wastewater.

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