Photocatalytic Activity of Sol-Gel Derived Bi2O3-TiO2 Nanocomposite

2012 ◽  
Vol 712 ◽  
pp. 73-83 ◽  
Author(s):  
C. Karunakaran ◽  
P. Magesan ◽  
P. Gomathisankar
Keyword(s):  
Visible Light ◽  
Deep Level ◽  
Anatase Phase ◽  
Sol Gel ◽  
Spherical Shape ◽  
Tween 80 ◽  
Electron Microscopic ◽  
Sem Images ◽  
X Ray ◽  
Crystallite Sizes

Bi2O3-TiO2 nanocomposites were obtained by sol-gel method using tween 80 (T-80) or polyvinyl pyrrolidone-polyethylene glycol (PVP-PEG) as templating agent. The powder X-ray diffraction (XRD) patterns of both the composites reveal the crystal structure of Bi2O3 as primitive tetragonal and TiO2 is in anatase phase. The energy dispersive X-ray (EDX) spectra provide the composition of Bi2O3 in Bi2O3-TiO2 (T-80) and Bi2O3-TiO2 (PVP-PEG) as 3.8 and 20.4 mol. %, respectively. The average crystallite sizes of Bi2O3-TiO2 (T-80) and Bi2O3-TiO2 (PVP-PEG), derived from XRD, are 9 and 17 nm, respectively. The scanning electron microscopic (SEM) images show the spherical shape of Bi2O3-TiO2 (T-80) and the composites are polycrystalline. The diffuse reflectance spectra (DRS) of the composites display faint absorption of visible light and strong absorption in UV-A region. The photoluminescence (PL) spectra of both the composites are similar and the observed near band gap emission (NBE) and deep level emission (DLE) agree with those of TiO2. The impedance spectra show that the charge-transfer resistances of the composites do not differ significantly. The visible light photoimpedance spectra display the photoconductance of Bi2O3-TiO2 (PVP-PEG) but not that of Bi2O3-TiO2 (T-80). Although the visible light-photocatalytic activities of the two nanocomposites to degrade dye do not differ significantly Bi2O3-TiO2 (T-80) under UV-A light degrades dyes faster than Bi2O3-TiO2 (PVP-PEG).

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>.

scholarly journals Antibacterial Activity of Ag-Doped TiO2 and Ag-Doped ZnO Nanoparticles

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Gebretinsae Yeabyo Nigussie ◽  
Gebrekidan Mebrahtu Tesfamariam ◽  
Berhanu Menasbo Tegegne ◽  
Yemane Araya Weldemichel ◽  
Tesfakiros Woldu Gebreab ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Zno Nanoparticles ◽  
Pathogenic Bacteria ◽  
Anatase Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Sem Images ◽  
X Ray ◽  
Doped Zno

We report in this paper antibacterial activity of Ag-doped TiO2 and Ag-doped ZnO nanoparticles (NPs) under visible light irradiation synthesized by using a sol-gel method. Structural, morphological, and basic optical properties of these samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrum, and UV-Vis reflectance. Room temperature X-ray diffraction analysis revealed that Ag-doped TiO2 has both rutile and anatase phases, but TiO2 NPs only have the anatase phase. In both ZnO and Ag-doped ZnO NPs, the hexagonal wurtzite structure was observed. The morphologies of TiO2 and ZnO were influenced by doping with Ag, as shown from the SEM images. EDX confirms that the samples are composed of Zn, Ti, Ag, and O elements. UV-Vis reflectance results show decreased band gap energy of Ag-doped TiO2 and Ag-doped ZnO NPs in comparison to that of TiO2 and ZnO. Pathogenic bacteria, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, were used to assess the antibacterial activity of the synthesized materials. The reduction in the viability of all the three bacteria to zero using Ag-doped ZnO occurred at 60 μg/mL of culture, while Ag-doped TiO2 showed zero viability at 80 μg/mL. Doping of Ag on ZnO and TiO2 plays a vital role in the increased antibacterial activity performance.

Photocatalytic Activity of Sm, Zr Co-Doped TiO2 Synthesized by Ultrasonic Assisted Sol-Gel Method

2013 ◽  
Vol 631-632 ◽  
pp. 399-403
Author(s):  
Xi Ming Luo ◽  
Fen Fen Li ◽  
Hong Tao Gao
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Ultrasonic Assisted ◽  
Uv Visible

Sm, Zr doped nanocrystalline TiO2 powers were prepared successfully by a facile ultrasonic assisted sol-gel method. The products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. X-ray diffraction peaks could be assigned to anatase TiO2, which confirms the crystallinity of the as-prepared samples. The SEM images demonstrated that the crystalinity is formed with spherical aggregates with average diameters ranging from 10 to 20 nm. The photocatalytic activity was studied on the photocatalytic degradation of methyl orange (MO) aqueous solution irradiated with UV-visible light. Under UV-visible light irradiation, the photocatalytic performances of the doped samples were much better than that of pure TiO2, and the co-dopant showed highest. It demonstrated that a strong Sm-Zr synergistic interaction might play a decisive role in driving the excellent photocatalytic performance of TiO2.

scholarly journals Visible Light Induced Photocatalytic Degradation of Methyl Red with Codoped Titania

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Susmitha Thota ◽  
Siva Rao Tirukkovalluri ◽  
Sreedhar Bojja
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Anatase Phase ◽  
Sol Gel ◽  
Visible Region ◽  
Oxygen Demand ◽  
Analytical Techniques ◽  
Active Species ◽  
Methyl Red ◽  
X Ray

Photocatalysis using semiconductor oxides was being investigated extensively for the degradation of dyes in effluent water. This paper reports our findings on visible light induced photocatalytic degradation of azo dye, methyl red mediated nitrogen and manganese codoped nano-titanium dioxide (N/Mn-TiO2). The codoped samples with varying weight percentages were synthesized by sol-gel method and characterized by various analytical techniques. The X-ray diffraction data showed that the synthesized samples were in anatase phase with 2θ at 25.3°. UV-visible diffuse reflectance spectral analysis revealed that the presence of dopants in TiO2 caused a significant absorption shift towards visible region and their presence was confirmed by X-ray photoelectron spectral data. The release of hydroxyl radical (major active species in photocatalytic degradation) by the photocatalyst in aqueous solution under visible light irradiation was quantitatively investigated by the photoluminiscent technique (PL). The effect of various experimental parameters like dopant concentration, pH, catalyst dosage, and initial dye concentrations was investigated and optimum conditions were established. The extent of mineralization of methyl red was studied by chemical oxygen demand (COD) assays and the results showed complete mineralization of the dye.

Synthesis of Mn-Doped ZnS Nanoparticles and Its Characterization

2020 ◽  
Vol 15 (1) ◽  
pp. 65-70
Author(s):  
F. F. Al-Harbi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Spherical Shape ◽  
Visible Range ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Zns Nanoparticles ◽  
X Ray ◽  
Crystallite Sizes ◽  
Mn Doped

ZnS powders doped with manganese (ZnS:Mn) was synthesized by the sol gel method. The structural and optical characteristics are studied using various techniques. Analysis with X-ray diffraction shows that cubic ZnS phase is formed with average crystallite sizes varying between 10 nm and 13 nm. There is no phase transformation due to Mn2+ doping. The formation of ZnS was confirmed by X-ray photoelectron spectroscopy (XPS) measurement. TEM images indicated the spherical shape of the nanoparticles. However, optical study has shown a strong reflectance in the visible range. The band gap (Eg) of ZnS:Mn is varied between 3.51 eV and 3.56 eV. The photoluminescence properties of ZnS:Mn nanopowders were studied.

scholarly journals Sulfur/Gadolinium-Codoped TiO2Nanoparticles for Enhanced Visible-Light Photocatalytic Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Eric S. Agorku ◽  
Bhekie B. Mamba ◽  
Avinash C. Pandey ◽  
Ajay K. Mishra
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Sol Gel ◽  
Indigo Carmine ◽  
Great Influence ◽  
Energy Dispersive ◽  
X Ray

A series of S/Gd3+-codoped TiO2photocatalysts were synthesized by a modified sol-gel method. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM)/energy-dispersive spectroscopy (EDS). Laboratory experiments with Indigo Carmine chosen as a model for organic pollutants were used to evaluate the photocatalytic performance of S/Gd3+-codoped TiO2under visible-light with varying concentrations of Gd3+ions in the host material. XRD and Raman results confirmed the existence of anatase phase TiO2with particle size ranging from 5 to 12 nm. Codoping has exerted a great influence on the optical responses along with red shift in the absorption edge. S/Gd3+-codoped TiO2showed significant visible-light induced photocatalytic activity towards Indigo Carmine dye compared with S-TiO2or commercial TiO2. TiO2-S/Gd3+(0.6% Gd3+) degraded the dye (ka= 5.6 × 10−2 min−1) completely in 50 min.

Effect of Chromium Doping on Visible Light Absorption of Nanosized Titania Sol-Gel

2009 ◽  
Vol 5 ◽  
pp. 95-104 ◽  
Author(s):  
J.A. Pedraza-Avella ◽  
R. López ◽  
F. Martínez-Ortega ◽  
E.A. Páez-Mozo ◽  
Ricardo Gómez
Keyword(s):  
Visible Light ◽  
Light Absorption ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Sol Gel ◽  
Visible Light Absorption ◽  
X Ray ◽  
Chromium Doping ◽  
Doped Titania

Visible light absorption of TiO2 can be induced by the addition of transition metal impurities. However, many dissimilar results have been reported about this subject and there are various interpretations about the origin of these absorption features. In this work, samples of chromium-doped titania (TiO2-Cr) with different dopant contents (0.1, 0.5, 1.0 and 5.0 wt. %) were prepared by a sol-gel method. Their particle size was determined by dynamic light scattering and it was on the nanometer scale (18 nm). X-ray powder diffraction and Raman spectroscopy showed only the presence of anatase phase in all samples. X-ray photoelectron spectroscopy reveals that the oxidation state of chromium in the prepared materials is different than in the dopant precursor. This change can be associated to the oxidative gelling conditions used in the materials preparation. UV VIS diffuse reflectance spectroscopy showed that the chromium doping, until 1.0 wt. %, did not effectively narrow the TiO2 band-gap but it induces the visible light absorption probably through the formation of color centers.

scholarly journals Cu-Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity

2018 ◽  
Vol 8 (11) ◽  
pp. 2067 ◽  
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 ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
Doped Tio2 ◽  
X Ray

Surface contamination by microbes is a major public health concern. A damp environment is one of potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO2) can effectively curb this growing threat. Metal-doped titania in anatase phase has been proven as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu)-doped TiO2 (Cu-TiO2) was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO2 was carried out via sol-gel technique. Cu-TiO2 further calcined at various temperatures (in the range of 500–700 °C) to evaluate the thermal stability of TiO2 anatase phase. The physico-chemical properties of the samples were characterized 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 TiO2 was maintained well, up to 650 °C, by the Cu dopant. UV–vis results suggested that the visible light absorption property of Cu-TiO2 was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasize the introduction of Cu+ and Cu2+ ions by replacing Ti4+ ions in the TiO2 lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9999%) was attained in 30 min of visible light irradiation by Cu-TiO2.

scholarly journals Photocatalytic Degradation of Dichlorvos in Visible Light byMg2+-TiO2Nanocatalyst

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
T. Siva Rao ◽  
Teshome Abdo Segne ◽  
T. Susmitha ◽  
A. Balaram Kiran ◽  
C. Subrahmanyam
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
Sem Images ◽  
Xps Spectra ◽  
X Ray ◽  
Adsorption Desorption

Photocatalytic activity of TiO2was studied by doping with magnesium (Mg2+-TiO2) with varying magnesium weight percentages ranging from 0.75–1.5 wt%. The doped and undoped samples were synthesized by sol-gel method and characterized by X-ray diffraction (XRD), N2adsorption-desorption (BET), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (DRS), and scanning electron microscopy (SEM). The XRD data has shown that anatase crystalline phase in Mg2+-TiO2catalysts, indicating that Mg2+ions did not influence the crystal patterns of TiO2. The presence of magnesium ions in TiO2matrix has been determined by XPS spectra. DRS spectra showed that there is a significant absorption shift towards the visible region for doped TiO2. The SEM images and BET results showed that doped catalyst has smaller particle size and highest surface area than undoped TiO2. The photocatalytic efficiency of the synthesized catalysts was investigated by the photocatalytic degradation of aqueous dichlorvos (DDVP) under visible light irradiation, and it was found that the Mg2+-doped catalysts have better catalytic activity than undoped TiO2. This can be attributed that there is a more efficient electron-hole creation in Mg2+-TiO2in visible light, contrary to undoped TiO2which can be excited only in UV irradiation. The effect of dopant concentration, pH of solution, dosage of catalysts, and initial pesticide concentration has been studied.

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>.

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