scholarly journals Blue to Yellow Photoluminescence Emission and Photocatalytic Activity of Nitrogen Doping in TiO2Powders

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Gabriela Byzynski ◽  
Caue Ribeiro ◽  
Elson Longo
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Oh Radical ◽  
Additional Energy ◽  
Photoluminescence Emission ◽  
Radical Production ◽  
N Doping ◽  
Band Gap Structure

The defects caused by doping are important for understanding the increased photocatalytic activities of TiO2:N in organic reactions and in the evaluation of OH radical production after doping. TiO2:N was therefore synthesized using a modified polymeric method and N doping was performed by calcination with urea. The resulting powders were characterized using field emission scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, Raman spectroscopy, Fourier transformation infrared spectroscopy, and photoluminescence emission spectroscopy (PL). N doping did not alter the morphology of the nanoparticles, and the anatase phase predominated, with the retention of the rutile phase. The band gap values, superficial areas, and crystallite sizes of the powders decreased after doping. The PL results showed an additional energy level in the TiO2:N band gap structure as a result of TiO2lattice defects caused by doping. At low N contents, the powders showed continuous emissions from the blue region to the yellow region and a high N content shifted the PL emissions to the red region. These results suggest that the use of these powders could increase the efficiencies of solar cells and water-splitting processes. The photocatalytic activity of the powders under UVC illumination was confirmed for different organic dye molecules. The OH radical production did not change extensively after doping, as shown by experiments with terephthalic acid, and higher photocatalytic efficiencies in Rhodamine-B degradation under UVC illumination were achieved using the doped samples.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

scholarly journals Fabrication, N-doping Mechanism and Evaluation of N-doped TiO2 Thin Films Based on Laser Ablation Method

2009 ◽  
Vol 2 (1) ◽  
pp. 17-23 ◽  
Author(s):  
S. Somekawa ◽  
Y. Kusumoto ◽  
H. Yang ◽  
M. Abdulla-Al-Mamun ◽  
B. Ahmmad
Keyword(s):  
Crystal Structure ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Laser Ablation ◽  
Anatase Phase ◽  
Rutile Phase ◽  
Laser Ablation Method ◽  
Dye Decomposition ◽  
N Doping ◽  
Keywords Laser

The relation among the change of the crystal structure, the amount of doped N and the photocatalytic activity for the decomposition of methylene blue was studied. The N-doping was promoted by the change of the crystal structure from the rutile phase to the anatase phase. The photocatalytic activity for the decomposition of methylene blue was enhanced by an increase in the amount of anatase crystals and doped N. Keywords: Laser ablation; N-doping process; Crystal change; N-doped TiO2 thin film; Dye decomposition. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.2992        J. Sci. Res. 2 (1), 17-23 (2010) 

scholarly journals Photoelectrochemical and theoretical investigation of the photocatalytic activity of TiO2 : N

RSC Advances ◽  
2016 ◽  
Vol 6 (92) ◽  
pp. 89687-89698 ◽  
Author(s):  
Gabriela Byzynski Soares ◽  
Renan Augusto Pontes Ribeiro ◽  
Sergio Ricardo de Lazaro ◽  
Caue Ribeiro
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Effective Mass ◽  
Theoretical Investigation ◽  
Hole Pair ◽  
Electron Hole ◽  
Electron Hole Pair ◽  
N Doping ◽  
Hole Recombination

In N-doping on TiO2 nanomaterial occurs a big decrease of band-gap (1 eV); however, its photocatalysis is low. We clarify such fact from effective mass, i.e., the electron–hole recombination is more than creation of electron–hole pair.

Europium Doped Titania Nanocomposites with Enhanced Photocatalytic Activity towards the Degradation of Partially Hydrolysis Polyacrylamide

2011 ◽  
Vol 391-392 ◽  
pp. 219-224
Author(s):  
Jin Huan Li ◽  
Hong Bo Fang ◽  
Wei Wang ◽  
Gui Fan Liu ◽  
Shao Dong Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Oil Recovery ◽  
Inductively Coupled Plasma ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Anatase Phase ◽  
Sol Gel ◽  
Pure Tio2 ◽  
Surface Shape ◽  
Titanium Tetraisopropoxide

Nanocrystals with different Eu3+ doping levels (%) were prepared by sol-gel and hydrothermal synthetic method using titanium tetraisopropoxide (TTIP) as titanium source. The products exhibited anatase phase structure, mesoporosity, and interesting surface compositions with three oxygen species and two titanium species. The crystallite sizes, crystal form, surface shape, composition and optical property of catalysts were characterized by X-ray diffraction patterns, UV-Vis diffuse reflectance spectroscopy, XPS and inductively coupled plasma atomic emission spectroscopy. The products were used as the photocatalysts to degrade a partially hydrolysis polyacrylamide (HPAM) under UV-light irradiation, a very useful polymer in oil recovery. For comparison, Degussa P25 and as-prepared pure TiO2 were also tested under the same conditions. The enhanced photocatalytic activity was obtained on as-prepared Eu3+ composites, and the reasons were explained.

scholarly journals Ultrasonication-Assisted Synthesis of ZnxCd1−xS for Enhanced Visible-Light Photocatalytic Activity

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 276
Author(s):  
Lei Yang ◽  
Maolin Zhang ◽  
Mingzhu Liu ◽  
You Fan ◽  
Haijie Ben ◽  
...  
Keyword(s):  
Solid Solution ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Degradation Mechanism ◽  
Hydrothermal Route ◽  
New Strategy ◽  
Stable Performance ◽  
Band Gap Structure ◽  
Gap Structure

ZnxCd1−xS as a solid solution photocatalyst has attracted widespread attention for its unique adjustable band gap structure and good and stable performance. A novel synthesis approach for ZnxCd1−xS is still required to further improve its performance. In this study, we synthesized a series of ZnxCd1−xS (x = 0−1) solid solutions via an ultrasonication-assisted hydrothermal route. In comparison with conventional methods of preparation, the sample prepared by our innovative method showed enhanced photocatalytic activity for the degradation of a methyl orange (MO) solution under visible light due to its high crystallinity and small crystallite size. Furthermore, the composition and bandgap of ZnxCd1−xS can be tuned by adjusting the mole ratio of Zn2+/Cd2+. Zn0.3Cd0.7S shows the highest level of activity and stability for the degradation of MO with k = 0.85 h−1, which is 2.2 times higher than that of CdS. The balance between band gap structure-directed redox capacity and light absorption of Zn0.3Cd0.7S accounts for its high photocatalytic performance, both of which are determined by the composition of the solid solution. Also, a degradation mechanism of MO over the sample is tentatively proposed. This study demonstrates a new strategy to synthesize highly efficient sulfide photocatalysts.

Comparison of the Photocatalytic Activity of N-Doped, P-Doped Titania under Solar Light Irradiation

2010 ◽  
Vol 113-116 ◽  
pp. 2141-2144
Author(s):  
Si Yao Guo ◽  
Bo Chi ◽  
Jin Bing Sun ◽  
Feng Lu Wang ◽  
Lin Yang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Band Gap Energy ◽  
Light Irradiation ◽  
Solar Light ◽  
Urea Solution ◽  
Solar Light Irradiation ◽  
N Doping ◽  
Doped Titania ◽  
Band Gap Narrowing

P-, N-doped titania were synthesized by the direct hydrothermal method, which phosphorus from phosphoric acid and the following nitridation from urea solution. The resulting materials were characterized by XRD, XPS analysis, and their photocatalytic activities were tested by the solar light irradiation. N-doping titania resulted in the band-gap narrowing with improved photocatalytic activity. However, the phosphated titania exhibited higher photocatalytic activity than the N-doped one, but with larger band-gap energy.

scholarly journals Synthesis, Characterization of Cu, S doped TiO2 and Its Photocatalytic Activity for Degradation of Remazol Black B

2019 ◽  
Vol 22 (2) ◽  
pp. 47-51 ◽  
Author(s):  
Abdul Haris ◽  
Gunawan Gunawan ◽  
Didik Setiyo Widodo ◽  
Rahmad Nuryanto ◽  
Retno Ariadi Lusiana ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Pore Volume ◽  
Energy Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Visible Region ◽  
Tio2 Photocatalyst ◽  
Remazol Black B ◽  
Bet Analysis ◽  
Remazol Black

Copper and sulfur modified TiO2(Cu-S-TiO2) photocatalyst was successfully synthesized using TiCl4, Cu(NO3)2.3H2O and H2SO4 as precursors by the sol-gel method andcalcination at 450°C for 4 hours. The synthesized photocatalyst was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Diffuse Reflectance Spectroscopy (DRS), Brunauer Emmett Teller (BET) method. The XRD results showed that the Cu-S-TiO2 photocatalyst had an anatase phase with a crystal grain size of 17.54 nm. However, the SEM image of the modified TiO2 showed inhomogeneous phase due to the crystal clustering of imperfect homogenization during the synthesis and sintering processes. The patterns of EDSof Cu-S-TiO2depicted the elements of Ti, O, Cu and S with doping of Cu and S c.a. 7 and 1%, respectively. Analysis using DRS UV-Vis showed Cu-S-TiO2 was able to shift the absorption of the TiO2 photocatalyst wavelength to the visible region with a band energy gap of 1.9 eV. The BET analysis results showed that the specific surface area (SBET), pore volume (Vp) and average pore volume radius (Dp) were measured from large Cu-S-TiO2, therefore Cu-S-TiO2 had good physicochemical and photocatalytic properties. The photocatalytic activity of 0.1 g Cu-S-TiO2 with 15 Watt tungsten light irradiation for 4 h was able to degrade 50 mL remazol black B 10 mg/L c.a. 92.60 %.

The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%. 

The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Sheikh Mohd Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%.

Preparation of Well-Ordered TiO2 Nanotube Arrays by Electrochemical Anodization of Titanium Foil in Neutral Electrolytes

2011 ◽  
Vol 233-235 ◽  
pp. 2047-2050
Author(s):  
Chao Wang ◽  
Da Chen ◽  
Shu Liu ◽  
Xia Ni Huang ◽  
Yue Xiang Huang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Solar Energy ◽  
Band Gap ◽  
High Performance ◽  
Diffuse Reflectance ◽  
Anatase Phase ◽  
Titanium Foil ◽  
Electrochemical Anodization ◽  
Nanotube Arrays

To obtain high performance TiO2nanotube arrays (TNAs)-based material is interesting because of its wide applications in photocatalysis field such as solar energy conversion, photocatalysis and sensors. In the present work, the well-ordered TNAs were prepared by electrochemical anodization of titanium foil in the SO42−/F−based electrolyte under 20 V for 2 h during which the Ti foil and Pt wire were used as anode and cathode, respectively. The FESEM results showed that the as-obtained TNAs were well-aligned on Ti substrate with ~ 1.5 μm in length and ~ 100 nm pore in diameter. The XRD results indicated that the as-formed TNAs was in the form of amorphous and could be transformed into crystalline anatase phase under the heat treatment at 450 °C. Meanwhile, the UV-vis diffuse reflectance spectra demonstrated that the band-gap of the obtained TNAs was narrower than the commercial TiO2nanoparticles, indicating a better photocatalytic activity of the as-prepared TNAs over the commercial TiO2nanoparticles.

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