scholarly journals Enhanced Photodecomposition of Methylene Blue in Water with Sr1−xKxTiO3−δ@PC-polyHIPEs under UV and Visible Light

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yonghua Gao ◽  
Tao Zhang ◽  
Qipeng Guo ◽  
Lizhen Gao
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Water Solution ◽  
Internal Phase ◽  
Water Pollutant ◽  
First Time

Photocatalytic method was investigated to remove water pollutant methylene blue (MB) produced in textile, plastic, and dye industries. PC-polyHIPEs were prepared by light-induced polymerization of dopamine in transparent polyHIPEs which were synthesized by polymerization within high internal phase emulsions. Sr1-xKxTiO3-δ (x = 0–0.5) nanoparticles were incorporated and adhered to PC-polyHIPEs to form Sr1-xKxTiO3-δ@PC-polyHIPEs for the first time. The catalysts were characterized by XRD, FTIR, TGA, UV-Vis DRS, and SEM and their photocatalytic properties for MB decomposition were measured over UV-Vis spectrometer. The PC-polyHIPEs were of interconnected porous structure with around 100 μm pores and 30 μm windows. Sr1−xKxTiO3−δ@PC-polyHIPEs showed excellent MB decomposition activity under either UV or visible light although Sr1−xKxTiO3−δ alone worked only under UV light. When x = 0.3, Sr1−xKxTiO3−δ@PC-polyHIPEs showed the highest photocatalytic performance due to the existence of more oxygen vacancies. When the water solution with 50 mg L−1 MB and 1.6 gcat. L−1 Sr0.7K0.3TiO3−δ@PC-polyHIPEs was exposed to visible light for 160 min at room temperature, 88.3% of MB was decomposed. After being used for eight cycles, 87.6% activity of fresh Sr0.7K0.3TiO3−δ@PC-polyHIPEs still remained. The influences of salinity, temperature, and catalyst concentration on the catalytic activity were studied. For MB decomposition under visible light, the activation energy of Sr0.7K0.3TiO3−δ@PC-polyHIPEs was calculated to be 12.3 kJ mol−1 and the kinetics analysis revealed that the photocatalysis followed the second-order reaction. These findings demonstrated that Sr1−xKxTiO3−δ@PC-polyHIPEs were an effective candidate for real application in decomposition of MB in water.

scholarly journals Visible-Light-Excited Room Temperature Phosphorescent Carbon Dots

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 464 ◽  
Author(s):  
Sizhe Hu ◽  
Kai Jiang ◽  
Yuci Wang ◽  
Sui Wang ◽  
Zhongjun Li ◽  
...  
Keyword(s):  
Solid State ◽  
Visible Light ◽  
Carbon Dots ◽  
Short Wavelength ◽  
Room Temperature ◽  
Uv Light ◽  
Long Wavelength ◽  
Heating Treatment ◽  
First Time ◽  
Matrix Free

Carbon dots (CDs) with a room temperature phosphorescent (RTP) feature have attracted considerable interest in recent years due to their fundamental importance and promising applications. However, the reported matrix-free RTP CDs only show short-wavelength (green to yellow) emissions and have to be triggered by ultraviolet (UV) light (below 400 nm), limiting their applications in certain fields. Herein, visible-light-excited matrix-free RTP CDs (named AA-CDs) with a long-wavelength (orange) emission are reported for the first time. The AA-CDs can be facilely prepared via a microwave heating treatment of L-aspartic acid (AA) in the presence of ammonia and they emit unique orange RTP in the solid state with visible light (420 nm) excitation just being switched off. Through the studies of the carbonization process, the C=O and C=N containing moieties in the AA-CDs are confirmed to be responsible for the observed RTP emission. Finally, the applications of AA-CDs in information encryption and anti-counterfeiting were preliminarily demonstrated.

scholarly journals Synthesis of Magnetic Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 Nanoparticles: The Photocatalytic Effects on Organic Pollutants upon Irradiation with UV-Vis Light

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 494 ◽  
Author(s):  
Mohammad Amin Marsooli ◽  
Mehdi Rahimi Nasrabadi ◽  
Mahdi Fasihi-Ramandi ◽  
Kourosh Adib ◽  
Saeid Pourmasoud ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Organic Pollutants ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Methyl Violet ◽  
Sem Images ◽  
X Ray ◽  
Magnetic Fe3o4

Magnetic Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 nanoparticles with different molar ratios of CeVO4 to other inorganic components were synthesized through co-precipitation with a sonochemical-assisted method. X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, vibrating sample magnetometry, and scanning electron microscopy (SEM) methods were used for the physico–chemical characterization of the obtained nanoparticles. As shown in the SEM images, the average sizes of the Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 nanoparticles that formed aggregates were approximately 50–70 nm and 80–100 nm, respectively. The photocatalytic performance of these nanoparticles was examined by measuring methylene blue degradation under visible light (assisted by H2O2). The sample with a mass ratio of 1:2:1 (Fe3O4/ZnWO4/CeVO4, S4) exhibited optimal photocatalytic performance, and thus this sample was subsequently used for the photodegradation of different organic pollutants upon irradiation with ultraviolet (UV) and visible light. Approximately 90% and 70% degradation of methyl violet and methylene blue, respectively, was observed after visible light irradiation. Additionally, the mechanism of the photocatalytic reaction was investigated by measuring ˙OH release under UV light in a system with terephthalic acid and by measuring the release of ˙O2−, ˙OH, and hole scavengers.

scholarly journals Efficient Charge Carrier Separation in l-Alanine Acids Derived N-TiO2 Nanospheres: The Role of Oxygen Vacancies in Tetrahedral Ti4+ Sites

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 698 ◽  
Author(s):  
Yongjuan Chen ◽  
Xiu Luo ◽  
Yao Luo ◽  
Peiwen Xu ◽  
Jiao He ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Charge Carrier ◽  
Visible Light ◽  
Oxygen Vacancies ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Charge Carriers ◽  
Tio2 Sample ◽  
Doped Tio2 ◽  
Efficient Charge

N-doped TiO2 with oxygen vacancies exhibits many advantages for photocatalysis, such as enhanced visible light absorbency, inhibition of the photogenerated charge carrier recombination, etc. However, preparation of N-doped TiO2 with oxygen vacancies under mild conditions is still a challenge. Herein, N-doped TiO2 nanospheres with tetrahedral Ti4+ sites were synthesized by using dodecylamine as template and assisted by l-alanine acids. The obtained samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis diffuse reflectance spectra (UV–Vis DRS). It was found that the dodecylamine as a neutral surfactant controlled the structure of TiO2 spherical, while l-alanine acids provided a nitrogen source. The existence of tetrahedral Ti4+ sites in N-doped TiO2 was also confirmed. The N-doped TiO2 sample with tetrahedral Ti4+ sites exhibited significantly improved photocatalytic performance for degradation of methylene blue solution under UV light or visible light irradiation. A combined time-resolved infrared (IR) spectroscopy study reveals that the enhanced photocatalytic performance could be attributed to a large amount of photogenerated charge carriers and efficient charge separation. It is demonstrated that the shallow donor state produced by oxygen vacancies of tetrahedral Ti4+ sites can effectively promote separation of charge carriers besides capturing electrons.

scholarly journals Zirconium-Doped Chromium IV Oxide Nanocomposites: Synthesis, Characterization, and Photocatalysis towards the Degradation of Organic Dyes

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Solid State ◽  
Room Temperature ◽  
Organic Dyes ◽  
Uv Light ◽  
Heterogeneous Photocatalysis ◽  
Ft Ir ◽  
Complete Mineralization

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.

Facile Preparation of Nanoporous SnO2 for Application in Photodegradation of Methylene Blue

2011 ◽  
Vol 194-196 ◽  
pp. 385-388
Author(s):  
Hong Juan Wang ◽  
Feng Qiang Sun ◽  
Ming Zhong Ren ◽  
Qing Wei Guo
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
High Photocatalytic Activity ◽  
N2 Adsorption ◽  
Photochemical Method ◽  
Degussa P25 ◽  
Adsorption Desorption

Nanoporous SnO2with high photocatalytic activity has been successfully prepared by a photochemical method, using SnCl2aqueous solution as a precursor. The as-synthesized sample was characterized by XRD, N2 adsorption-desorption and UV-vis. The photocatalytic activity of the sample was evaluated by degrading methylene blue (MB) aqueous solution under the UV light source and was compared with that of the commercial titania (Degussa P25). The results showed that the produced SnO2can degrade MB solution quickly and has comparative photocatalytic performance with P25 for degrading MB. This facile method supplies an effective way to prepare SnO2photocatalyst.

Synthesis of Visible-Light Responsive CdS/ZnO Nanocomposite Photocatalysts via Simple Precipitation Method

2014 ◽  
Vol 608 ◽  
pp. 224-229 ◽  
Author(s):  
Potjanaporn Chaengchawi ◽  
Karn Serivalsatit ◽  
Pornapa Sujaridworakun
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Precipitation Method ◽  
Cds Nanoparticles ◽  
Methylene Blue Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Blue Solution ◽  
Scanning Electron

A visible-light responsive CdS/ZnO nanocomposite photocatalyst was successfully synthesized by precipitation of CdS nanoparticles, using Cd (NO3)2 and Na2S as starting materials, on ZnO nanoparticles and then calcined at 400°C for 2 hours. The effects of the mole ratio of CdS and ZnO in the composites on their phase, morphology, and surface area were investigated by X-ray Diffraction (XRD), scanning electron microscope (SEM), Brunauer Emmett Teller method (BET), respectively. The photocatalytic degradation of methylene blue solution in the presence of composite products under visible-light irradiation was investigated. The results showed that the mole ratio of CdS and ZnO played a significant role on photocatalytic performance. The highest photocatalytic activity was obtained from the CdS/ZnO nanocomposite with mole ratio of 1:4, which is higher than that of pure CdS and pure ZnO.

l-Asparagine-assisted synthesis of flower-like β-Bi2O3 and its photocatalytic performance for the degradation of 4-phenylphenol under visible-light irradiation

RSC Advances ◽  
2015 ◽  
Vol 5 (91) ◽  
pp. 74977-74985 ◽  
Author(s):  
Xin Xiao ◽  
Shunheng Tu ◽  
Chunxia Zheng ◽  
Huan Zhong ◽  
Xiaoxi Zuo ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Light Irradiation ◽  
Temperature Range

By introducing l-asparagine as a ligand, a flower-like precursor of Bi2O3 was prepared by a simple reflux process under atmospheric pressure. β-Bi2O3 was then conveniently obtained by decomposing the precursor and stabilized in a temperature range from room temperature to 420 °C due to the surface-coordination effects of CO32− derived from l-asparagine.

Visible light-induced C–H sulfenylation using sulfinic acids

2017 ◽  
Vol 19 (20) ◽  
pp. 4785-4791 ◽  
Author(s):  
Pengfei Sun ◽  
Daoshan Yang ◽  
Wei Wei ◽  
Min Jiang ◽  
Zuli Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Sulfur Source ◽  
Sulfinic Acids ◽  
First Time ◽  
Direct Use

The direct use of sulfinic acids as an odorless sulfur source to construct hetroaryl sulfides through a photoredox process has been realized at room temperature for the first time.

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