scholarly journals Enhanced photocatalytic degradation of Remazol Black under visible light illumination through S doped TiO2 (S-TiO2) nanoparticles: Operational factors and kinetic study

2021 ◽  
Vol 23 (2) ◽  
pp. 323-332
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Kinetic Study ◽  
Bandgap Energy ◽  
Light Illumination ◽  
Specular Reflectance ◽  
Transmission Electron ◽  
Light Region ◽  
Remazol Black

<p>The degradation of Remazol Black (RBB) by S-TiO2 photocatalyst was investigated. X-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV-vis specular reflectance spectroscopy has been used to characterize S-TiO2. The results suggested that the optical absorption edge of TiO2 was red-shifted by the addition of S dopants and the bandgap energy was 3.02 eV. The sulfur species were found to be evenly dispersed on the TiO2 crystal lattice as cationic sulfur (S6+) which corresponds to the cationic substitution on TiO2. The particle size decreased to 4-14 nm after S doping, which indicates that the addition of S dopants has contributed to an improvement in the photocatalyst surface area. The degradation of RBB was achieved 94% after 120 min visible light irradiation, a remarkable increase compared to bare TiO2 which was only able to degrade 48% of RBB at the same time. Optimization of the pH showed that the optimum pH for RBB degradation was 3.0, and the photocatalyst dose was 0.8 g L-1. Kinetic study showed that S-TiO2 photocatalytic degradation of RBB followed the pseudo-second-order kinetics model. Reducing the bandgap has been found to increase the activity of photodegradation in the visible light region.</p>

ENHANCED VISIBLE-LIGHT-DRIVEN PHOTOCATALYTIC DEGRADATION PERFORMANCE OF CIP ON BiVO4–Bi2WO6 NANO-HETEROJUNCTION PHOTOCATALYSTS

NANO ◽  
2014 ◽  
Vol 09 (02) ◽  
pp. 1450015 ◽  
Author(s):  
SHAOFANG SUN ◽  
YAFAN WU ◽  
XIAN ZHANG ◽  
ZHONGJIE ZHANG ◽  
YAN YAN ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Degradation Ratio ◽  
Band Position ◽  
Visible Light Driven

The removal of CIP from the environment has become a mandatory issue. In our paper, we have realized the visible-light-driven degradation of CIP on the BiVO 4– Bi 2 WO 6 nano-heterojunction photocatalysts. The synthesized photocatalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-Vis) absorption spectra and photoluminescence (PL) spectra. Compared with the single-phase BiVO 4 and Bi 2 WO 6 counterparts, BiVO 4– Bi 2 WO 6 nano-heterojunction photocatalysts show enhanced photocatalytic degradation activities in visible-light-driven CIP degradation. Particularly, when R( Bi 2 WO 6∕ BiVO 4) = 10 wt .%, the products exhibit the highest CIP degradation ratio in 60 min of 76.8% under visible light illumination. The tentative mechanism of the interface charge transfer (IFCT) effect in the BiVO 4– Bi 2 WO 6 heterojunction structure is also discussed by using the band position calculation.

One-Step Hydrothermal Synthesis of Bi2S3-TiO2-RGO Composites with Enhanced Visible Light Photocatalytic Activities

NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850051 ◽  
Author(s):  
Yanan Li ◽  
Zhongmin Liu ◽  
Yaru Li ◽  
Yongchuan Wu ◽  
Jitao Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Photogenerated Electron ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Photocatalytic Ability ◽  
Transmission Electron ◽  
Light Region ◽  
Infrared Spectrometer ◽  
One Step

The Bi2S3-TiO2-RGO composites were synthesized by a facile one-step hydrothermal method and applied for the photocatalytic degradation of Rhodamine B (Rh B) under the visible light. The Bi2S3-TiO2-RGO composites were characterized by transmission electron microscopy, X-ray diffraction, Raman and Fourier transform infrared spectrometer. The results indicated that the Bi2S3-TiO2-RGO composites were successfully prepared, and Ti-O-C and S-C bonds were existing among Bi2S3, TiO2 as well as RGO. Furthermore, the photocatalytic ability of Bi2S3-TiO2-RGO composites was excellent under visible light due to its responding to the whole visible light region, low recombination rate of photogenerated electron–hole pairs and relatively negative conduction band. Rh B photocatalytic degradation rate was 99.5% after 50[Formula: see text]min and still could reach 98.4% after five cycles. Finally, a formation mechanism as well as a photocatalytic mechanism of Bi2S3-TiO2-RGO composites were proposed based on the experimental results.

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.

SYNTHESIS OF CROSS Bi2 WO6 MICROWAFERS WITH ENHANCED PHOTOCATALYTIC ACTIVITY UNDER VISIBLE LIGHT IRRADIATION

2012 ◽  
Vol 19 (01) ◽  
pp. 1250005 ◽  
Author(s):  
GUIZHEN WANG ◽  
GENGPING WAN ◽  
SHIWEI LIN
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance Spectrum ◽  
Orthorhombic Phase ◽  
Transmission Electron ◽  
Light Region ◽  
Uv Visible ◽  
Visible Diffuse Reflectance Spectrum ◽  
Better Than

Novel cross Bi2 WO6 microwafers have been fabricated by a facile acetone-assisted solvothermal method in high quantity. The structure characterizations of the microwafers were investigated in detail by means of X-ray powder diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. The results indicate that the orthorhombic phase of Bi2 WO6 with high crystallinity can be obtained and each microwafer is polycrystalline in nature and organized by the nanoflake subunits. UV-visible diffuse reflectance spectrum of the prepared Bi2 WO6 microwafers demonstrates that they have absorption in the visible light region. The photocatalytic activity of cross Bi2 WO6 microwafers toward (Rhodamine B) RhB degradation under visible light was investigated, and it was found to be significantly better than that of Bi2 WO6 sample prepared by solid-state reaction (SSR-Bi2 WO6) .

Fe-doped TiO2/SiO2 Aerogel Microspheres for Visible Light Photocatalysis Degradation of Methylene Blue

2011 ◽  
Vol 239-242 ◽  
pp. 2993-2996 ◽  
Author(s):  
Ming Xian Liu ◽  
Li Hua Gan ◽  
Da Zhang Zhu ◽  
Zi Jie Xu ◽  
Zhi Xian Hao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Visible Light ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Visible Light Photocatalysis ◽  
Photocatalytic Ability ◽  
Transmission Electron ◽  
Light Region ◽  
20 Nm

In this paper, we present a strategy for the preparation of Fe-doped TiO2/SiO2aerogel microspheres (Fe-TSAMs) for visible light photocatalysis degradation of methylene blue. A water- in-oil (W/O) emulsion of Span 80–Tween 85/n-heptane–n-butanol/FeCl3-doped TiO2/SiO2alcoholic sols–formamide was obtained. Wet TiO2/SiO2gel microspheres were prepared by the sol-gel process in the W/O emulsion, then they were dried at ambient pressure condition to prepare Fe-TSAMs. The Fe-TSAMs were characterized by N2adsorption and desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the resultant Fe-TSAMs possess nanoporous network structure comprising TiO2and SiO2nanoparticles with diameters of 10-20 nm. The Fe-TSAMs have a mean diameter of about 100 μm, an apparent density of 0.26 g/cm3, a specific surface area of 360 m2/g, a pore volume of 1.77 cm3/g and the most probable pore size of 18.7 nm with the porosity of 87.7%. By using methylene blue as a simulated aqueous pollutant, the visible light photocatalysis properties of the Fe-TSAMs were investigated. The results indicate that low concentration Fe ion doping (5 wt%) could avoid the formation of recombination centers for photo-generated electron/hole pairs. Compared with commercial P25 TiO2powders, Fe-TSAMs exhibit excellent photocatalytic ability for degradation of methylene blue under visible light region. The Fe-TSAMs could be reclaimed conveniently and the reused Fe-TSAMs also have a good photocatalytic activity.

Preparation of ZnS quantum dot photocatalyst and study on photocatalytic degradation of antibiotics

2019 ◽  
Vol 9 (5) ◽  
pp. 413-418
Author(s):  
Maobin Wei ◽  
Lili Yang ◽  
Yongsheng Yan ◽  
Liang Ni
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Quantum Dot ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Photocatalytic Property ◽  
Catalytic Performance ◽  
Structure And Morphology ◽  
Transmission Electron

In this paper, ZnS quantum dot nanomaterials were prepared by means of hydrothermal method and the structure and morphology of the prepared samples were characterized by XRD and transmission electron microscopy (TEM). At the same time, the photocatalytic properties of ZnS quantum dots were studied using antibiotic contaminants ciprofloxacin (CIP) in the environment as the object of degradation. The study showed that the successfully prepared ZnS quantum dot has good photocatalytic property under UV irradiation, it can effectively degrade the antibiotic contaminant ciprofloxacin in the environment, but its catalytic performance under visible light is not high and its degradation efficiency is only 45.75%.

scholarly journals Bi5O7I/g-C3N4 Heterostructures With Enhanced Visible-Light Photocatalytic Performance for Degradation of Tetracycline Hydrochloride

2021 ◽  
Vol 9 ◽  
Author(s):  
Yang Yang ◽  
Min Lai ◽  
Jialei Huang ◽  
Jinze Li ◽  
Ruijie Gao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Species ◽  
Tetracycline Hydrochloride ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
P Type ◽  
Active Intermediates

Bi5O7I/g-C3N4 p-n junctioned photocatalysts were synthesized by alcohol-heating and calcination in air. The structures, morphologies and optical properties of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy (DRS). Photocatalytic activity of the heterojunctioned composites were evaluated by degradation of Rhodamine B (RhB) and tetracycline hydrochloride (TCH) under visible light illumination. The results indicated that the composites exhibited superior efficiencies for photodegradation of RhB and TCH in comparison with pure BiOI, Bi5O7I and g-C3N4. An effective built-in electric field was formed by the interface between p-type Bi5O7I and n-type g-C3N4, which promoted the efficient separation of photoinduced electron-hole pairs. In addition, 8% Bi5O7I/g-C3N4 composite showed excellent photostability in a five-cycle photocatalytic experiment. Experiments on scavenging active intermediates revealed the roles of active species.

SYNTHESIS OF Bi2WO6 MICROSPHERES WITH VISIBLE-LIGHT-DRIVEN PHOTOCATALYTIC PROPERTIES

2013 ◽  
Vol 12 (05) ◽  
pp. 1350035 ◽  
Author(s):  
GENGPING WAN ◽  
GUIZHEN WANG
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Large Scale ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Light Region ◽  
Visible Light Driven ◽  
Uv Visible

Bi 2 WO 6 microspheres constructed from nanosheets have been synthesized by a controllable solvothermal route in a large scale. The structure characterizations of the microspheres were investigated in detail by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). On the basis of XRD analysis and SEM observation of the products at different reaction time periods, a growth mechanism of Bi 2 WO 6 microspheres was proposed. UV-Visible diffuse reflectance (DR) spectrum of the prepared Bi 2 WO 6 microspheres demonstrates that they have absorption in the visible light region. The photocatalytic activity of Bi 2 WO 6 microspheres toward Rhodamine-B ( RhB ) degradation was investigated and the as-prepared products exhibited good photocatalytic activity in degradation of RhB under 300 W Xe lamp light irradiation.

scholarly journals Controlled Synthesis of CuS and Cu9S5 and Their Application in the Photocatalytic Mineralization of Tetracycline

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 899
Author(s):  
Murendeni P. Ravele ◽  
Opeyemi A. Oyewo ◽  
Damian C. Onwudiwe
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Sulfides ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Pure Phase ◽  
Pure Phases

Pure-phase Cu2−xS (x = 1, 0.2) nanoparticles have been synthesized by the thermal decomposition of copper(II) dithiocarbamate as a single-source precursor in oleylamine as a capping agent. The compositions of the Cu2−xS nanocrystals varied from CuS (covellite) through the mixture of phases (CuS and Cu7.2S4) to Cu9S5 (digenite) by simply varying the temperature of synthesis. The crystallinity and morphology of the copper sulfides were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), which showed pure phases at low (120 °C) and high (220 °C) temperatures and a mixture of phases at intermediate temperatures (150 and 180 °C). Covellite was of a spherical morphology, while digenite was rod shaped. The optical properties of these nanocrystals were characterized by UV−vis–NIR and photoluminescence spectroscopies. Both samples had very similar absorption spectra but distinguishable fluorescence properties and exhibited a blue shift in their band gap energies compared to bulk Cu2−xS. The pure phases were used as catalysts for the photocatalytic degradation of tetracycline (TC) under visible-light irradiation. The results demonstrated that the photocatalytic activity of the digenite phase exhibited higher catalytic degradation of 98.5% compared to the covellite phase, which showed 88% degradation within the 120 min reaction time using 80 mg of the catalysts. The higher degradation efficiency achieved with the digenite phase was attributed to its higher absorption of the visible light compared to covellite.

scholarly journals ZnO Nanoparticles with Controllable Ce Content for Efficient Photocatalytic Degradation of MB Synthesized by the Polyol Method

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Gregorio Flores-Carrasco ◽  
Micaela Rodríguez-Peña ◽  
Ana Urbieta ◽  
Paloma Fernández ◽  
María Eugenia Rabanal
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Degradation ◽  
Doping Concentration ◽  
Polyol Method ◽  
Transmission Microscopy ◽  
Uv Illumination ◽  
Transmission Electron ◽  
Optical Luminescence ◽  
Pl Emission ◽  
Ce Content

This paper reports on the synthesis of Ce-doped ZnO (CZO) nanoparticles (NPs) by an alternative polyol method at low temperature. The method, facile and rapid, uses acetate-based precursors, ethylene glycol as solvent, and polyvinylpyrrolidone as capping agent. The effects of the Ce-doping concentration (ranging from 0 to 8.24 atomic%) on the structural, morphological, compositional, optical, luminescence, and photocatalytic properties of the NPs were investigated by several techniques. The structural findings confirmed that the CZO NPs have a typical hexagonal wurtzite-type structure with a preferred orientation along the (101) plane. The results obtained by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) revealed that the NPs size decreased (from ~30 to ~16 nm) with an increase in the Ce-doping concentration. Energy Dispersive X-Ray Spectroscopy (EDS) and High Resolution Transmission Microscopy (HRTEM) results confirmed the incorporation of Ce ions into the ZnO lattice. Ce-doping influences the photoluminescence (PL) emission compared to that of pure ZnO. The PL emission is related to the presence of different kinds of defects, which could take part in charge transfer and/or trapping mechanisms, hence playing an essential role in the photocatalytic activity (PCA). In fact, in this work we report an enhancement of PCA as a consequence of Ce-doping. In this sense, the best results were obtained for samples doped with 3.24 atomic%, that exhibited a photocatalytic degradation efficiency close to 99% after 60 min ultraviolet (UV) illumination, thus confirming the viability of Ce-doping for environmental applications.

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