Photoreduction of Dye with Noble Metal Gold Permeated with Metal Oxide Titania

2020 ◽  
Vol 20 (6) ◽  
pp. 3896-3901 ◽  
Author(s):  
Jyoti Bansal ◽  
A. K. Hafiz ◽  
Shailesh Narain Sharma
Keyword(s):  
Metal Oxide ◽  
Noble Metals ◽  
Irradiation Time ◽  
Visible Region ◽  
Visible Absorption ◽  
Photo Degradation ◽  
Sunlight Irradiation ◽  
Tunable Bandgap ◽  
Photo Response ◽  
Uv Visible

Photoactive degradation of textile malachite green (MG), methylene blue (MB) dyes has been permeated on metal oxide TiO2 nanoparticles under sunlight. Semiconductor photocatalysis is a promising method for removal of toxic chemicals from wastewater produced by industry. Due to tunable bandgap, TiO2 among various semiconductor studied mostly. Large band gap (UV active) and recombination of exciton in TiO2 less active in photo degradation. Noble metals such as gold nanoparticles deposited on TiO2 surface increased the optical activity and to shift optical response to visible region. Degradation detail has been carried out by characterisation such as XRD, UV-Vis, PL, TEM, and SEM for MG and MB textile dyes under sunlight irradiation. UV-visible absorption spectra and PL spectra shows that photo-response of as prepared sample is extended from UV to visible region. PL intensity decreases with increases in concentration of Au nanoparticles, decreases in intensity in optical spectra of Au–TiO2 composites shows that charge transfer process dominates. Au–TiO2 plays an essential role in enhancing photocatalytical activity. Decolorization optimization depends on catalyst concentration, Dye concentration, light intensity and, irradiation time.

scholarly journals Preparation of Fe-DopedTiO2Nanotubes and Their Photocatalytic Activities under Visible Light

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang
Keyword(s):  
Visible Light ◽  
Visible Region ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Ultrasonic Assisted ◽  
Uv Visible

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.

Self-Generated Macrochannel-Structure TiO2/g-C3N4 with High Photocatalytic Activity

2016 ◽  
Vol 69 (4) ◽  
pp. 478 ◽  
Author(s):  
Gaopeng Dai ◽  
Tao Wang ◽  
Suqin Liu ◽  
Ying Liang ◽  
Wen Xu
Keyword(s):  
Photocatalytic Activity ◽  
High Photocatalytic Activity ◽  
Tetrabutyl Titanate ◽  
Mixed Solution ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Sunlight Irradiation ◽  
Photocatalytic Activities ◽  
Uv Visible ◽  
Oxidative Species

TiO2/g-C3N4 composites with macrochannel structure were successfully synthesised without using templates by the simple dropwise addition of tetrabutyl titanate containing graphitic carbon nitride (g-C3N4) to a water-ethanol mixed solution, which was then calcined at 400°C. The as-prepared samples were characterised by X-ray diffraction, scanning electron microscopy, and UV-visible absorption spectroscopy. The photocatalytic activities of the samples were evaluated by the photocatalytic degradation of methyl orange in an aqueous medium under visible-light and simulated sunlight irradiation. The results show that the g-C3N4 content in TiO2/g-C3N4 composites plays an important role in the formation of macrochannels. Only samples containing less than 10 wt-% of g-C3N4 exhibit macrochannel structure. TiO2/g-C3N4 composites with macrochannel structure displayed enhanced photocatalytic activity. G-C3N4 content exhibited an obvious influence on photocatalytic performance, and the optimal loading of g-C3N4 was 10 wt-%. The enhanced photocatalytic activity could be attributed to the synergetic effects of the macrochannel structure, the large specific surface area, and the heterojunction between TiO2 and g-C3N4. The main oxidative species responsible for the photodegradation of pollutants were further confirmed by the trapping experiments.

scholarly journals Perovskite-structured CaTiO3 coupled with g-C3N4 as a heterojunction photocatalyst for organic pollutant degradation

2018 ◽  
Vol 9 ◽  
pp. 671-685 ◽  
Author(s):  
Ashish Kumar ◽  
Christian Schuerings ◽  
Suneel Kumar ◽  
Ajay Kumar ◽  
Venkata Krishnan
Keyword(s):  
Photocatalytic Activity ◽  
Organic Pollutant ◽  
Visible Region ◽  
Active Species ◽  
Sunlight Irradiation ◽  
Organic Pollutant Degradation ◽  
Mixing Method ◽  
Plausible Mechanism ◽  
Uv Visible ◽  
Degradation Of Pollutants

A novel graphitic carbon nitride (g-C3N4)–CaTiO3 (CTCN) organic–inorganic heterojunction photocatalyst was synthesized by a facile mixing method, resulting in the deposition of CaTiO3 (CT) nanoflakes onto the surface of g-C3N4 nanosheets. The photocatalytic activity of the as-synthesized heterojunction (along with the controls) was evaluated by studying the degradation of an aqueous solution of rhodamine B (RhB) under UV, visible and natural sunlight irradiation. The CTCN heterojunction with 1:1 ratio of g-C3N4/CT showed the highest photocatalytic activity under sunlight irradiation and was also demonstrated to be effective for the degradation of a colorless, non-photosensitizing pollutant, bisphenol A (BPA). The superior photocatalytic performance of the CTCN heterojunction could be attributed to the appropriate band positions, close interfacial contact between the constituents and extended light absorption (both UV and visible region), all of which greatly facilitate the transfer of photogenerated charges across the heterojunction and inhibit their fast recombination. In addition, the two-dimensional (2D) morphology of g-C3N4nanosheets and CT nanoflakes provides enough reaction sites due to their larger surface area and enhances the overall photocatalytic activity. Furthermore, the active species trapping experiments validate the major role played by superoxide radicals (O2 −•) in the degradation of pollutants. Based on scavenger studies and theoretically calculated band positions, a plausible mechanism for the photocatalytic degradation of pollutants has been proposed and discussed.

scholarly journals Synthesis, Characterization, and Investigation of Visible Light Photocatalytic Activity of C Doped TiO2/CdS Core-Shell Nanocomposite

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Atul B. Lavand ◽  
Yuvraj S. Malghe ◽  
Suraj H. Singh
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Region ◽  
Cds Nanoparticles ◽  
Core Shell ◽  
Visible Absorption ◽  
X Ray ◽  
Visible Light Photocatalytic Activity ◽  
Uv Visible ◽  
Visible Light Photocatalytic

Carbon (C) doped TiO2/CdS core-shell nanocomposite (C/TiO2/CdS) was synthesized using microemulsion method. Synthesized powder was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and UV-visible spectrophotometery. TEM images reveal that C/TiO2/CdS core-shell heterostructure is successfully prepared with CdS as a core and C doped TiO2 as a shell. UV-visible absorption spectra show that CdS nanoparticles act as a sensitizer and effectively enhance the photoabsorption capacity of C/TiO2/CdS nanocomposite in visible region. Visible light photocatalytic activity of synthesized nanocomposite was evaluated for the degradation of methylene blue. C/TiO2/CdS core-shell nanocomposite exhibits better photocatalytic activity as compared to bare TiO2, CdS, CdS/TiO2, and C doped TiO2.

scholarly journals Interfacial Polycondensation Synthesis of Optically Sensitive Polyurea Microcapsule

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Weidong Lai ◽  
Xinzheng Li ◽  
Huiqing Liu ◽  
Lu Han ◽  
Yajun Zhao ◽  
...  
Keyword(s):  
Irradiation Time ◽  
Bond Cleavage ◽  
Core Shell ◽  
Interfacial Polycondensation ◽  
Visible Absorption ◽  
Polymer Formation ◽  
Thermal Phase ◽  
Image Density ◽  
Change Temperature ◽  
Uv Visible

TMPTA prepolymer resin and photoinitiators of ITX/TPO had been encapsulated in core-shell structured microcapsules as optical responding ingredients based on interfacial polycondensation method, and polyurea structured microcapsule shell had been formed on the sheared O/W interface. The synthesized microcapsule had regular core-shell structure with the diameter of about 0.455 μm and shell thickness of about 40 nm. UV-visible absorption spectra indicated that the encapsulated ITX and TPO photoinitiators could efficiently absorb UV irradiation. Under exposure, the C=C bonds absorbance of the microencapsulated TMPTA decreased rapidly and then nearly unchanged during further exposure after 30 s. This implied that the optical response was achieved by C=C bond cleavage of TMPTA monomer initiated by the photoinitiator radicals, to form network polymers in microcapsules. The relative crosslinking rate was about 50%. Due to core polymer formation, the thermal phase change temperature of exposed microcapsules was narrowed and ranged from 105 to 205°C, compared with that from 125 to 260°C of unexposed microcapsules. Furthermore, the image density decrease at longer irradiation time had also verified the optical responding function of the synthesized microcapsules in macroscopic viewpoint.

scholarly journals Enhanced Photocatalytic and Antibacterial Activities of K2Ti6O13 Nanowires Induced by Copper Doping

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 400 ◽  
Author(s):  
Weiwei Zhang ◽  
Xin Wang ◽  
Yuanhui Ma ◽  
Haoran Wang ◽  
Yumin Qi ◽  
...  
Keyword(s):  
Effective Means ◽  
Sol Gel ◽  
Visible Region ◽  
Antibacterial Activities ◽  
Visible Absorption ◽  
Cu Doping ◽  
Sunlight Irradiation ◽  
High Antibacterial Activity ◽  
Antibacterial Performance ◽  
Hydrothermal Methods

Cu-doped K2Ti6O13 (Cu–KTO) nanowires were prepared using a combination of sol–gel and hydrothermal methods to improve the photocatalytic and antibacterial performance of K2Ti6O13 (KTO) nanowires. The Cu–KTO nanowires maintained the monoclinic structure of KTO. The Cu2+ ions could enter into the lattice of KTO by substituting for certain Ti4+ ions and cause the formation of defects and oxygen vacancies. The UV–Visible absorption spectra showed that after Cu doping, the absorption edge of KTO moved to the visible region, indicating that the band gap decreased and the ability to absorb visible light was acquired. The photocatalytic properties of the Cu–KTO nanowires with different doping amounts were assessed by simulating the photodegradation of rhodamine B (RhB) under simulated sunlight irradiation. The 1.0 mol% Cu–KTO nanowires showed the best photocatalytic performance, and 91% of RhB was decomposed by these nanowires (the catalyst dose was only 0.3 g/L) within 5 h. The performance of the Cu–KTO nanowires was much better than that of the KTO nanowires. The Cu–KTO nanowires also showed high antibacterial activity for Escherichia coli (ATCC 25922) of up to 99.9%, which was higher than that of the pure KTO samples. Results proved that Cu doping is an effective means to develop multifunctional KTO nanomaterials. It can be used to degrade organic pollutants and remove harmful bacteria simultaneously in water environments.

Template-Free Sonochemical Preparation of ZnO Cauliflower-Like Microstructures

2010 ◽  
Vol 663-665 ◽  
pp. 125-128
Author(s):  
Chong Hai Deng ◽  
Han Mei Hu ◽  
Shang Lin Wang ◽  
Guo Quan Shao
Keyword(s):  
Large Scale ◽  
Broad Band ◽  
Visible Region ◽  
Ambient Condition ◽  
Ultraviolet Region ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Template Free ◽  
Uv Visible

Cauliflower-like ZnO superstructures composed of nanoparticles in large scale were successfully synthesized only using Zn(CH3COO)2•2H2O and triethanolamine (TEA) aqueous solution mixtures via a template-free sonochemical process at the ambient condition. A number of techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-visible absorption and photoluminescence (PL) were used to characterize the obtained ZnO products. It has been interestingly found that UV-Vis absorption spectrum shows not only a weak and sharp peak at 367 nm in ultraviolet region but also a strong and broad band centered at 564 nm in visible region. The possible formation mechanism of ZnO cauliflower-like structure is also proposed.

scholarly journals Chemical and Plant Mediated Synthesis of La2O3 Nanoparticles and Comparison of their Structural, Antibacterial, Photocatalytic and Optical Properties

2021 ◽  
Vol 33 (3) ◽  
pp. 570-576
Author(s):  
A. Swetharanyam ◽  
R. Kunjitham
Keyword(s):  
Leaf Extract ◽  
Saed Pattern ◽  
Bandgap Energy ◽  
Visible Absorption ◽  
Sunlight Irradiation ◽  
Gram Positive Bacteria ◽  
Good Antibacterial Activity ◽  
Optical Bandgap Energy ◽  
Uv Visible ◽  
Polar Extracts

The La2O3 nanoparticles have been synthesized successfully with a chemical and biosynthesized method. The optical bandgap energy and of chemically synthesized or biosynthesized (M. oppositifolia and T. portlacaustrum leaf extract) La2O3 nanoparticles was calculated from UV-visible absorption between 5.10, 4.26 and 4.46 eV. The good polycrystalline cubic nature of synthesized La2O3 nanoparticles was evident from the bright circular SAED pattern, consistent with the XRD outcome. It is clear that the non-polar extracts could function as stabilizers for La2O3 nanoparticles through attachment to the counterions. The La2O3 nanoparticles have been used as efficient photocatalyst to degrade acid black 1 dye under sunlight irradiation. Besides, this biocatalyst showed excellent ability to degrade biosynthesized La2O3 nanoparticles (T. portlacaustrum) under visible light irradiation 87%. Synthesis of La2O3 nanoparticles by green chemistry process presented good antibacterial activity against Gram-negative and Gram-positive bacteria.

scholarly journals Straightforward Synthesis of Mn3O4/ZnO/Eu2O3-Based Ternary Heterostructure Nano-Photocatalyst and Its Application for the Photodegradation of Methyl Orange and Methylene Blue Dyes

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4661
Author(s):  
Jayachamarajapura Pranesh Shubha ◽  
Haralahalli Shivappa Savitha ◽  
Syed Farooq Adil ◽  
Mujeeb Khan ◽  
Mohammad Rafe Hatshan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Methyl Orange ◽  
Irradiation Time ◽  
Solar Irradiation ◽  
Anionic Dyes ◽  
One Pot ◽  
Sunlight Irradiation ◽  
Ft Ir ◽  
Degradation Activity ◽  
Ecological Applications

Zinc oxide-ternary heterostructure Mn3O4/ZnO/Eu2O3 nanocomposites were successfully prepared via waste curd as fuel by a facile one-pot combustion procedure. The fabricated heterostructures were characterized utilizing XRD, UV–Visible, FT-IR, FE-SEM, HRTEM and EDX analysis. The photocatalytic degradation efficacy of the synthesized ternary nanocomposite was evaluated utilizing model organic pollutants of methylene blue (MB) and methyl orange (MO) in water as examples of cationic dyes and anionic dyes, respectively, under natural solar irradiation. The effect of various experimental factors, viz. the effect of a light source, catalyst dosage, irradiation time, pH of dye solution and dye concentration on the photodegradation activity, was systematically studied. The ternary Mn3O4/ZnO/Eu2O3 photocatalyst exhibited excellent MB and MO degradation activity of 98% and 96%, respectively, at 150 min under natural sunlight irradiation. Experiments further conclude that the fabricated nanocomposite exhibits pH-dependent photocatalytic efficacy, and for best results, concentrations of dye and catalysts have to be maintained in a specific range. The prepared photocatalysts are exemplary and could be employed for wastewater handling and several ecological applications.

Remarkable kinetic stability of α-thiocarbamoyl substituted 4-methoxybenzylcations

1998 ◽  
Vol 76 (12) ◽  
pp. 1910-1915 ◽  
Author(s):  
Robert A McClelland ◽  
Victoria E Licence ◽  
John P Richard ◽  
Kathleen B Williams ◽  
Shrong-Shi Lin
Keyword(s):  
Key Words ◽  
Strong Interaction ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Visible Absorption ◽  
Methyl Group ◽  
Thioamide Group ◽  
Azide Ion ◽  
Uv Visible ◽  
Leaving Groups

4-Methoxybenzyl cations bearing α-(N,N-dimethylcarbamoyl) and α-(N,N-dimethylthiocarbamoyl) substituents have been generated photochemically upon irradiation of precursors with pentafluorobenzoate or 4-methoxybenzoate leaving groups. The ions have been observed with flash photolysis in 40:60 acetonitrile:water and in 50:50 methanol:water, and rate constants were measured for their decay in solvent alone and for their capture by azide ion. The cations so studied and their lifetimes in 40% acetonitrile are 6, ArC+H-CONMe2, 0.6 μs; 2, ArC+H-CSNMe2, 7 ms; and 4, ArC+(CH3)-CSMe2, 6 ms, where Ar = 4-MeOC6H4. The cation 4 reacts with solvent by elimination of a proton from the α-methyl group, and the rate constant for solvent addition must be less than 1 s-1. The CSNMe2 substituted cations are 105-107-fold longer lived than analogs where the thioamide group has been replaced with an α-methyl. The UV-visible absorption spectra of these two cations also show significant differences from those of typical 4-methoxybenzyl cations. Thus, both the lifetimes and spectra point to a strong interaction of the benzylic centre with the thioamide group. Key words: flash photolysis, thiocarbamoyl stabilized carbocation, photosolvolysis.

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