scholarly journals Electrochemical Investigation of Doped Titanium Dioxide

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
J. W. J. Hamilton ◽  
J. A. Byrne ◽  
C. McCullagh ◽  
P. S. M. Dunlop
Keyword(s):  
Transition Metals ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Sol Gel ◽  
Response Spectra ◽  
Light Irradiation ◽  
Photocurrent Response ◽  
Defect Level ◽  
Current Time ◽  
Potential Dependence

Thin films of transition-metal doped (0.2, 1.0, and 5.0 atom%)TiO2were prepared on titanium foil using a sol-gel route catalyzed by ammonium acetate. Dopants investigated were the fourth-period transition metals. The prepared films were characterised by Raman spectroscopy, Auger electron spectroscopy, and photoelectrochemical methods. The films doped with transition metals showed a lower photocurrent response than undoped samples. No major red shift in the photocurrent response spectra of the doped films was observed. A photocurrent response was observed under visible light irradiation of the samples and was potential dependent peaking around−0.3 V (SCE), which is indicative of electron promotion from a filled defect level. Examination of the defect level potential dependence by analysis of the current-time response under chopped illumination at fixed potential (−0.8 V–+1.07 V) gave a good correlation with the potential dependence observed in the visible light irradiation studies.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

Dehydrogenative 6π Heterocyclization under Visible Light Irradiation and Mechanistic Insights

2021 ◽  
Author(s):  
Zhao Zhang ◽  
Haohua Chen ◽  
Niklas Keller ◽  
Qin Xiong ◽  
Lei Liu ◽  
...  
Keyword(s):  
Transition Metals ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Reaction Proceeds ◽  
Visible Light Driven

A visible-light-driven oxidative 6π heterocycilization for the synthesis of structurally diverse π-conjugated polycyclic 1-aminoisoquinolines has been developed. The reaction proceeds under visible-light or sunshine, obviates photocatalyst and transition-metals, and features...

scholarly journals Visible-enhanced photocatalytic performance of CuWO4/WO3 hetero-structures: incorporation of plasmonic Ag nanostructures

2018 ◽  
Vol 42 (13) ◽  
pp. 11109-11116 ◽  
Author(s):  
R. Salimi ◽  
A. A. Sabbagh Alvani ◽  
N. Naseri ◽  
S. F. Du ◽  
D. Poelman
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Light Irradiation ◽  
Photo Degradation ◽  
Gel Method ◽  
Sol Gel Method

A new plasmonic Ag hybridized CuWO4/WO3 heterostructured nanocomposite was successfully synthesized via a ligand-assisted sol gel method and the photocatalytic activity was evaluated by photo-degradation of methylene blue (MB) under visible light irradiation.

Photocatalyst- and transition-metal-free α-allylation of N-aryl tetrahydroisoquinolines mediated by visible light

2020 ◽  
Vol 22 (3) ◽  
pp. 646-650 ◽  
Author(s):  
Zhuohua Li ◽  
Pengju Ma ◽  
Yongzhu Tan ◽  
Yufei Liu ◽  
Min Gao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Metal Free

A convenient and efficient α-allylation of N-aryl tetrahydroisoquinolines has been achieved. This transformation can be realized under only visible light irradiation without the aid of transition metals or photocatalysts.

scholarly journals BiOCl/TiO2/diatomite composites with enhanced visible-light photocatalytic activity for the degradation of rhodamine B

2019 ◽  
Vol 10 ◽  
pp. 1412-1422 ◽  
Author(s):  
Minlin Ao ◽  
Kun Liu ◽  
Xuekun Tang ◽  
Zishun Li ◽  
Qian Peng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Light Irradiation ◽  
Molar Ratio ◽  
Visible Light Photocatalytic Activity ◽  
Visible Light Photocatalytic

A BiOCl/TiO2/diatomite (BTD) composite was synthesized via a modified sol–gel method and precipitation/calcination method for application as a photocatalyst and shows promise for degradation of organic pollutants in wastewater upon visible-light irradiation. In the composite, diatomite was used as a carrier to support a layer of titanium dioxide (TiO2) nanoparticles and bismuth oxychloride (BiOCl) nanosheets. The results show that TiO2 nanoparticles and BiOCl nanosheets uniformly cover the surface of diatomite and bring TiO2 and BiOCl into close proximity. Rhodamine B was used as the target degradation product and visible light (λ > 400 nm) was used as the light source for the evaluation of the photocatalytic properties of the prepared BTD composite. The results show that the catalytic performance of the BTD composite under visible-light irradiation is much higher than that of TiO2 or BiOCl alone. When the molar ratio of BiOCl to TiO2 is 1:1 and the calcination temperature is 400 °C, the composite was found to exhibit the best catalytic effect. Through the study of the photocatalytic mechanism, it is shown that the strong visible-light photocatalytic activity of the BTD composite results mainly from the quick migration of photoelectrons from the conduction band of TiO2/diatomite to the surface of BiOCl, which promotes the separation effect and reduces the recombination rate of the photoelectron–hole pair. Due to the excellent catalytic performance, the BTD composite shows great potential for wide application in the field of sewage treatment driven by solar energy.

Characteristics and Photocatalytic Activity of TiO2 Thin Film Sensitized with a Porphyrin Dye

2008 ◽  
Vol 8 (5) ◽  
pp. 2699-2702 ◽  
Author(s):  
K. S. Yao ◽  
D. Y. Wang ◽  
C. Y. Chang ◽  
W. Y. Ho ◽  
L. Y. Yang
Keyword(s):  
Thin Film ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Sol Gel ◽  
Indigo Carmine ◽  
Erwinia Carotovora ◽  
Visible Spectral Region ◽  
Plant Diseases ◽  
Light Irradiation

In this study, a novel porphyrin dye, 5, 10, 15, 20-tetraphenyl-21H, 23H-porphine nickel (TPPN) doped TiO2 (TiO2/TPPN) thin film with visible light respondency was prepared using a sol–gel method and characterized with XRD, SEM, UV-Vis instruments. The observation showed that the absorption edge of TPPN dye-doped thin film shifted into the visible light region. The photocatalytic indigo carmine degradation results showed that under visible light irradiation (λ > 400 nm) for 6 hrs, the photocatalytic activity of TiO2 thin film sensitized with 200 μM of TPPN dye showed the best performance, with an indigo degradation ratio up to 96%. Moreover, the TiO2/TPPN thin film showed a relevant photocatalytic bactericidal effect on Erwinia carotovora subsp. carotovora 7 induced vegetable soft rot disease in the visible spectral region. Evidence for the photocatalytic disinfection technique against a plant pathogen under visible light irradiation will have potential for direct application in future control of plant diseases in irrigation water systems.

Treatment of textile wastewater under visible LED lamps using CuO/ZnO nanoparticles immobilized on scoria rocks

RSC Advances ◽  
2015 ◽  
Vol 5 (92) ◽  
pp. 75474-75482 ◽  
Author(s):  
F. Mahdizadeh ◽  
S. Aber
Keyword(s):  
Thin Films ◽  
Water Treatment ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Zno Nanoparticles ◽  
Sol Gel ◽  
Textile Wastewater ◽  
Light Irradiation ◽  
Direct Crystallization ◽  
Crystallization Method

ZnO and CuO thin films were synthesized by a sol–gel and direct crystallization method on granular porous natural scoria respectively and CuO/ZnO/scoria was used for water treatment under visible light irradiation.

N-Loaded TiO2 for Photocatalytic Degradation of Methyl Orange under Visible Light Irradiation

2012 ◽  
Vol 622-623 ◽  
pp. 883-888
Author(s):  
Natkritta Boonprakob ◽  
Natda Wetchakun ◽  
Sukon Phanichphant ◽  
Jun Chen ◽  
Burapat Inceesungvorn
Keyword(s):  
Methyl Orange ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Light Irradiation ◽  
Gap Energy ◽  
Visible Light Driven ◽  
Degradation Of Methyl Orange

Nitrogen-loaded TiO2(N-loaded TiO2), a visible-light driven catalyst, was successfully synthesized by the modified sol-gel method. Physical characterizations of the as-prepared catalysts have been performed by using X-ray diffraction (XRD), Diffuse reflectance UVvisspectroscopy(DRUVvis), Raman spectroscopyand BETspecific surface areain order to obtain structure-activity relationship. Results from Raman spectroscopy clearly suggested that N atoms were incorporated into the TiO2crystal lattice as evidenced by the vibrational peak of TiN in TiO2-xNx.DR UVvis results also suggested that the nitrogen dopant might be responsible for narrowing the TiO2band gap energy, thus resulting in a shift towards the visiblelight region. Photocatalytic activity of N-loaded TiO2evaluated through the degradation of methyl orange (MO)under visible light irradiation (l> 400 nm) indicated that all N-loaded photocatalysts exhibited significantly higher activities than the unloaded TiO2and Degussa P25 TiO2. According to the results from DR UV-vis, XRD and BET studies, the enhanced photoactivity observed from N-loaded samples might be due to a decrease in TiO2band gap energy and/or changes in chemical and physical properties of the materials upon loading with nitrogen.

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