scholarly journals One-Pot Template-Free Hydrothermal Synthesis of Monoclinic Hollow Microspheres and Their Enhanced Visible-Light Photocatalytic Activity

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Bei Cheng ◽  
Wenguang Wang ◽  
Lei Shi ◽  
Jun Zhang ◽  
Jingrun Ran ◽  
...  
Keyword(s):  
Visible Light ◽  
Monoclinic Phase ◽  
Ostwald Ripening ◽  
Diffuse Reflectance Spectroscopy ◽  
Hollow Spheres ◽  
Hollow Microspheres ◽  
High Yield ◽  
Infrared Spectrometry ◽  
One Pot ◽  
Template Free

Monoclinic-phase BiVO4hollow microspheres with diameters of about 2–4 μm have been successfully fabricated in high yield by a one-pot template-free hydrothermal route. The reaction duration and urea concentration are shown to play important roles in the formation of the BiVO4hollow microspheres. X-ray diffraction, scanning electron microscopy, nitrogen adsorption-desorption isotherms, fourier transform infrared spectrometry, and UV-visible diffuse reflectance spectroscopy are used to characterize the products. The results show that all the as-prepared BiVO4samples have monoclinic phase structure and exhibit good crystallinity. A formation mechanism for the BiVO4hollow spherical structure via a localized Ostwald ripening is proposed based on the experimental observations. In addition, studies of the photocatalytic properties by exposure to visible light irradiation demonstrate that the as-obtained BiVO4hollow spheres show potential photocatalytic application. Hydroxyl radicals (•OH) are not detected on the surface of visible-light-illuminated BiVO4by the photoluminescence technique, suggesting that•OH is not the dominant photooxidant and photogenerated hole could directly take part in photocatalytic reaction. The prepared BiVO4hollow spheres are also of great interest in pigment, catalysis, separation technology, biomedical engineering, and nanotechnology.

scholarly journals Template-Free Fabrication of Bi2WO6 Hierarchical Hollow Microspheres with Visible-Light-Driven Photocatalytic Activity

Energies ◽  
2016 ◽  
Vol 9 (10) ◽  
pp. 764 ◽  
Author(s):  
Yuxue Zhou ◽  
Xiangdong Meng ◽  
Ling Tong ◽  
Xianghua Zeng ◽  
Xiaobing Chen
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Hollow Microspheres ◽  
Visible Light Driven ◽  
Template Free

Immobilization of BiOBr/BiOI Hierarchical Microspheres on Fly Ash Cenospheres as Visible Light Photocatalysts

2016 ◽  
Vol 69 (1) ◽  
pp. 119 ◽  
Author(s):  
Li Lin ◽  
Ya Wang ◽  
Manhong Huang ◽  
Donghui Chen
Keyword(s):  
Photocatalytic Activity ◽  
Fly Ash ◽  
Visible Light ◽  
Diffuse Reflectance Spectroscopy ◽  
Three Dimensional ◽  
One Pot ◽  
Transmission Electron ◽  
Hierarchical Microspheres ◽  
2D Nanosheets ◽  
Fly Ash Cenospheres

Three-dimensional (3D) BiOBr/BiOI hierarchical microspheres were successfully fabricated on the surface of fly ash cenospheres (FACs) via a facile one-pot solvothermal method for the first time. The as-prepared samples were characterized by XRD, SEM, energy-dispersive X-ray spectroscopy, UV–visible diffuse reflectance spectroscopy, and high-resolution transmission electron microscopy. The results indicated that the loaded hierarchical microspheres exhibited a uniform distribution, and some aggregation was observed. These well-dispersed hierarchical microspheres were composed of 2D nanosheets, which possess heterojunction structures. Based on the photodegradation tests examining the removal of rhodamine B from water under visible light irradiation (λ > 420 nm), the photocatalytic activity of BiOB/BiOI/FACs was superior to that of BiOBr/FACs and BiOI/FACs. A proposed mechanism for the enhanced photocatalytic activity displayed by BiOB/BiOI/FACs is discussed.

Visible Light-Promoted C–C Bond Formation from Hydroxyaryls in Water

2019 ◽  
Vol 72 (12) ◽  
pp. 978 ◽  
Author(s):  
Dafne Saporito ◽  
Sergio A. Rodriguez ◽  
Maria T. Baumgartner
Keyword(s):  
Visible Light ◽  
Bond Formation ◽  
High Yield ◽  
Reaction Yield ◽  
Halogen Lamp ◽  
One Pot ◽  
Direct Arylation ◽  
Photoinduced Reactions ◽  
Optical Applications ◽  
Very High

An eco-friendly and direct arylation of hydroxyaryls in water using photoinduced reactions with different substrates (1-bromo-2-naphthol, 1-iodo-2-naphthol, N-(2-iodophenyl)acetamide, 5-bromouracil, 2-iodo-N-methylbenzamide, and 2-iodobenzamide) was studied. For example, π-expanded coumarins, compounds with potential optical applications, were synthesized in very high yield, without the use of toxic reagents, in a one-pot reaction. In addition, we demonstrate that the irradiation source (halogen lamp) can be efficiently replaced by an LED without altering the reaction yield.

scholarly journals Synthesis of TiO2/Pd and TiO2/PdO Hollow Spheres and Their Visible Light Photocatalytic Activity

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Jing Yan ◽  
Xiaojuan Li ◽  
Bo Jin ◽  
Min Zeng ◽  
Rufang Peng
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Hollow Spheres ◽  
Active Species ◽  
Degradation Efficiency ◽  
Diffraction Field ◽  
Transmission Electron

A series of TiO2, TiO2/Pd, and TiO2/PdO hollow sphere photocatalysts was successfully prepared via a combination of hydrothermal, sol-immobilization, and calcination methods. The structure and optical properties of the as-prepared samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Telleranalysis, Barrett-Joyner-Halenda measurement, and UV-Vis diffuse reflectance spectroscopy. The photocatalysis efficiencies of all samples were evaluated through the photocatalytic degradation of rhodamine B under visible light irradiation. Results indicated that TiO2/PdO demonstrated a higher photocatalytic activity (the photocatalytic degradation efficiency could reach up to 100% within 40 min) than the other samples and could maintain a stable photocatalytic degradation efficiency for at least four cycles. Finally, after using different scavengers, superoxide and hydroxyl radicals were identified as the primary active species for the effectiveness of the TiO2/PdO photocatalyst.

Fe-Doped UiO-66 Combined with ZnIn2S4 for Adsorption and Degradation of RhB Under Visible Light

NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050089
Author(s):  
Litong Niu ◽  
Shaoping Hu ◽  
Yali Ma ◽  
Mingming Wang ◽  
Bolin Lv ◽  
...  
Keyword(s):  
Visible Light ◽  
Electrochemical Impedance ◽  
Diffuse Reflectance Spectroscopy ◽  
Photogenerated Electron ◽  
Impedance Spectrum ◽  
Solvothermal Reaction ◽  
Electrochemical Impedance Spectrum ◽  
X Ray Diffraction ◽  
One Pot ◽  
Ft Ir

Novel ZnIn2S4/FeUiO-66 (ZFeU) photocatalyst with different proportion of FeUiO-66 has been successfully prepared by a facile one-pot solvothermal reaction. The as-synthesized nanocomposites have been thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Brunauer–Emmett–Teller (BET) characterization, photoluminescence (PL) analysis and electrochemical impedance spectrum (EIS). The photocatalytic performance of ZFeU nanocomposites for the photodegradation of RhB under visible light irradiation was better than that of ZnIn2S4 and FeUiO-66 alone. The experiment results showed the 20% ZFeU nanocomposites had the best photocatalytic properties. At the same time, a probable mechanism was discussed and it was believed that introduction of FeUiO-66 on ZnIn2S4 would minimize the recombination of photogenerated electron-hole pairs, leading to the enhancement of the photocatalytic activity.

scholarly journals Facile Synthesis and Photocatalytic Property of Titania/Carbon Composite Hollow Microspheres with Bimodal Mesoporous Shells

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Guohong Wang ◽  
Bei Cheng ◽  
Jun Zhang ◽  
Lin Xu ◽  
Tingting Yin
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Hollow Spheres ◽  
Photocatalytic Property ◽  
Nitrogen Adsorption ◽  
Carbon Composite ◽  
Hollow Microspheres ◽  
Calcination Time ◽  
One Pot ◽  
Pore Structures

Titania/carbon composite hollow microspheres with bimodal mesoporous shells are one-pot fabricated by hydrothermal treatment of the acidic (NH4)2TiF6aqueous solution in the presence of glucose at180∘C for 24 h and then calcined at450∘C. The as-prepared samples were characterized by XRD, SEM, TEM, HRTEM, UV-visible spectroscopy, and nitrogen adsorption-desorption isotherms. The photocatalytic activity of the as-prepared samples was evaluated by daylight-induced photocatalytic decolorization of methyl orange aqueous solution at ambient temperature. The effects of calcination time on the morphology, phase structure, crystallite size, specific surface area, pore structures, and photocatalytic activity of the microspheres were investigated. The results indicated that the as-obtained TiO2/C composite hollow spheres generally exhibit bimodal mesopore size distribution with their peak intra-aggregated mesopore size in the range of 2.3–4.5 nm and peak interaggregated mesopore size in the range of 5.7–12.7 nm, depending on specific calcination time. The daylight-induced photoactivity of as-obtained hollow TiO2/C microspheres generally exceeds that of Degussa P25. The influences of calcination time on the photoactivity are discussed in terms of carbon content, phase structures, and pore structures.

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