scholarly journals Enhanced Photocatalytic Degradation of Phenol Using Urchin-Like ZnO Microrod-Reduced Graphene Oxide Composite under Visible-Light Irradiation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Phenol Degradation ◽  
Hydrothermal Process ◽  
Light Irradiation ◽  
Light Illumination ◽  
Order Kinetic ◽  
Phenol Solution ◽  
Vis Spectroscopy

In this study, visible-light-driven ZnO microrod-rGO heterojunction composites were successfully synthesized via a facile and scalable hydrothermal process. The prepared photocatalyst heterojunction was examined using different techniques including XRD, SEM, FTIR, UV-Vis spectroscopy, and TGA to reveal their crystal phase, morphology, and other optical properties. The photocatalytic performance of the obtained ZnO-rGO composites was measured by the photodegradation of phenol under visible light illumination. The addition of graphene over the catalyst exhibited an enhanced photocatalytic activity for phenol degradation due to its high surface area and decreasing rate of electron-hole separation. Kinetic studies proved that the degradation of phenol process happened by following the pseudo-first-order kinetic model. The effective conditions for degradation of phenol using ZnO-rGO composite were 0.2 g L-1catalyst dose, pH -4, and initial concentration 20 ppm of phenol solution. Comparing with ZnO microrods, the heterojunction composite degraded the organic pollutants of phenol solution up to 84.2% of efficiency displaying the highest photocatalytic activity, whereas urchin-like ZnO catalyst exhibited much less photocatalytic activity for phenol degradation under visible light irradiation. This result envisages immense properties, showing a great potential industrial application for the removal of phenolic wastewater.

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.

Ultrathin HNb3O8 nanosheets with oxygen vacancies for enhanced photocatalytic oxidation of amines under visible light irradiation

2019 ◽  
Vol 7 (10) ◽  
pp. 5493-5503 ◽  
Author(s):  
Junli Chen ◽  
Hai Wang ◽  
Zhiqiang Zhang ◽  
Lifeng Han ◽  
Yonghui Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Oxidation ◽  
Oxygen Vacancies ◽  
Hydrothermal Process ◽  
Light Irradiation ◽  
Excellent Photocatalytic Activity ◽  
Simple Hydrothermal Process

Ultrathin HNb3O8 nanosheets with oxygen vacancies were successfully synthesized by a simple hydrothermal process. HNb3O8 NSs showed excellent photocatalytic activity.

Controllable Synthesis and Photocatalytic Activity of Ba0.6Mg0.4TiO3 Particles with Different Morphologies

2014 ◽  
Vol 955-959 ◽  
pp. 2267-2275 ◽  
Author(s):  
Rong Liu ◽  
Shi Duo Zhao ◽  
Xue Lin
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Hydrothermal Process ◽  
Light Irradiation ◽  
Photocatalytic Properties ◽  
X Ray Diffraction ◽  
Photocatalytic Activities ◽  
Uv Visible ◽  
Xrd Patterns

Ba0.6Mg0.4TiO3 (BMT) particles with different morphologies were synthesized through hydrothermal method and their optical and photocatalytic properties were investigated. Their crystal structure and microstructures were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). XRD patterns demonstrate that the as-prepared samples are tetragonal structure. FESEM shows that BMT crystals can be fabricated in different morphologies by simply manipulating the reaction parameters of hydrothermal process. The UV-visible diffuse reflectance spectra (UV-vis DRS) reveal that the band gaps of BMT photocatalysts are about 2.37 - 2.51 eV. The as-prepared BMT photocatalysts exhibite higher photocatalytic activities in the degradation of methyl orange (MO) under visible light irradiation (λ > 420 nm) compared with traditional N-doped TiO2 (N-TiO2) and pure BaTiO3 (BTO). The high photocatalytic performance of BMT photocatalysts could be attributed to the recombination restraint of the e-/h+ pairs resulting from doping of Mg2+ ions. The influence of morphologies upon the photocatalytic properties of BMT was studied. Furthermore, BMT nanowires reveal the highest photocatalytic activity. Up to 94.0% MO is decolorized after visible light irradiation for 360 min.

High Photocatalytic Activity of Oliver-Like BiVO4 for Rhodamine B Degradation under Visible Light Irradiation

2018 ◽  
Vol 876 ◽  
pp. 52-56 ◽  
Author(s):  
Huu Vinh Nguyen ◽  
Tran Van Thuan ◽  
Sy Trung Do ◽  
Duy Trinh Nguyen ◽  
Dai Viet Nguyen Vo ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Ethylene Glycol ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Mixed Solvent ◽  
Hydrothermal Process ◽  
Monomethyl Ether ◽  
High Specific Surface Area ◽  
Light Irradiation

We report the facial synthesis of BiVO4crystals with different morphologies by the solvothermal and hydrothermal process. The phase structure and morphology as-synthesized samples were characterized by XRD, FE-SEM, and UV-vis DRS spectroscopy. We also investigated the photocatalytic activity of BiVO4for the decomposition of rhodamine B (RhB) under visible light irradiation. The results showed that oliver-like BiVO4was obtained when using the mixed solvent of ethylene glycol and water while starflower-like BiVO4was obtained using the mixed solvent of ethylene glycol monomethyl ether and water. The hydrothermal evolution process the BiVO4product with a rod-like morphology. Oliver-like BiVO4with pure monoclinic scheelite phase and high specific surface area exhibits efficient photodegradation of RhB (k = 7.82x10-3min-1).

Nitrogen and Lanthanum Co-Doped TiO2 with Enhanced Photocatalytic Activity

2011 ◽  
Vol 179-180 ◽  
pp. 192-196
Author(s):  
Ye Cong ◽  
Peng Qin ◽  
Xuan Ke Li ◽  
Zhi Jun Dong ◽  
Guan Ming Yuan
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Nitrogen Doping ◽  
Hydrothermal Process ◽  
Utilization Efficiency ◽  
Light Irradiation ◽  
Lanthanum Doping ◽  
Co Doping ◽  
Co Doped

Nitrogen and lanthanum co-doped nanocsystalline titania photocatalysts were prepared by a homogeneous precipitation-hydrothermal process. The photocatalytic activity of the prepared samples on photodegradation of rhodamine B in visible light irradiation was studied. The nitrogen and lanthanum co-doping could greatly improve the photocatalytic activity of titania in visible light irradiation, probablely due to a synergistic effect of co-doping. The nitrogen doping could narrow the band gap of titania and enhance the utilization efficiency of visible light, while the lanthanum doping could accelerate the separation of photo-generated electrons and holes. Furthermore, the lanthanum doping could increase the adsorption of organic pollutants on the surface of photocatalyst.

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 Thickness Dependent on Photocatalytic Activity of Hematite Thin Films

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Yen-Hua Chen ◽  
Kuo-Jui Tu
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Film Thickness ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Hexagonal Structure ◽  
Light Irradiation ◽  
Light Illumination ◽  
Photocatalytic Ability

Hematite (Fe2O3) thin films with different thicknesses are fabricated by the rf magnetron sputtering deposition. The effects of film thicknesses on the photocatalytic activity of hematite films have been investigated. Hematite films possess a polycrystalline hexagonal structure, and the band gap decreases with an increase of film thickness. Moreover, all hematite films exhibit good photocatalytic ability under visible-light irradiation; the photocatalytic activity of hematite films increases with the increasing film thickness. This is because the hematite film with a thicker thickness has a rougher surface, providing more reaction sites for photocatalysis. Another reason is a lower band gap of a hematite film would generate more electron-hole pairs under visible-light illumination to enhance photocatalytic efficiency. Experimental data are well fitted with Langmuir-Hinshelwood kinetic model. The photocatalytic rate constant of hematite films ranges from 0.052 to 0.068 min-1. This suggests that the hematite film is a superior photocatalyst under visible-light irradiation.

scholarly journals Photocatalytic activity of RBi2O4NO3 (R: Tb, Dy, Er, Gd, and Ho) for phenol degradation under visible light irradiation

2021 ◽  
Vol 129 (3) ◽  
pp. 181-186
Author(s):  
Md SAIDUZZAMAN ◽  
Nami TSUCHIOKA ◽  
Fumiya NORITAKE ◽  
Nobuhiro KUMADA ◽  
Takahiro TAKEI
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Phenol Degradation ◽  
Light Irradiation

Photocatalytic Activity of Neodymium Ion Doped TiO2 for 2-Mercaptobenzothiazole Degradation under Visible Light Irradiation

2005 ◽  
Vol 2 (2) ◽  
pp. 130 ◽  
Author(s):  
Fang Bai Li ◽  
Xiang Zhong Li ◽  
Kok Wai Cheah
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Optimal Dosage ◽  
Light Illumination ◽  
Significant Activity ◽  
Analytical Results ◽  
Neodymium Ion

Environmental Context. Conventional titanium dioxide catalysts can assist oxidation reactions upon ultraviolet light irradiation. Such photocatalysts are used to degrade organic pollutants in water to less harmful inorganic materials. By modifying the catalyst with luminescent lanthanide ions, the pollutant degradation reaction takes place upon visible light illumination. 2-Mercaptobenzothiazole, a poorly biodegradable and malodourous pollutant used both as a corrosion inhibitor and antifungal agent, is shown to be efficiently mineralized to carbon dioxide, water, ammonium, nitrate, and sulfate with this new catalyst. Abstract. A series of neodymium ion-doped titanium dioxide (Nd3+-TiO2) catalysts were prepared by means of a sol–gel method. The physical and chemical properties of the catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) N2 sorbtion method, UV-visible diffusive reflective spectroscopy (DRS), and photoluminescence (PL) analyses. The adsorption behaviour and photocatalytic activity of Nd3+-TiO2 under visible light irradiation were evaluated for aqueous 2-mercaptobenzothiazole (MBT) solution. The analytical results of XRD and BET demonstrate that the neodymium ion doping could reduce the crystallite size and increase the specific surface area of TiO2 catalysts. The analytical results of DRS show that Nd3+ doping did not shift the main absorption band edge significantly, but some new absorption peaks attributable to 4f internal electron transition existed in the visible region. It was further confirmed that significant PL emission occurred in the visible range of 350–700 nm, attributable to the electron transfer between Nd3+ and TiO2 owing to introduction of a Nd 4f level. The experimental results of adsorption isotherm tests demonstrate that both the saturated adsorption amount (Γmax) and adsorption equilibrium constant (Ka) of Nd3+-TiO2 catalysts increased significantly with the increased Nd3+ dosage. Furthermore, the Nd3+-TiO2 catalysts demonstrated significant activity towards photocatalytic degradation of MBT in aqueous solution under visible light irradiation, whereas the TiO2 catalyst did not. An optimal dosage of Nd3+ doping was found to be 0.7%. We propose that the introduction of the Nd 4f level plays a crucial role in visible photosensitization and enhancement of the electron–hole separation.

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