Sensitization of TiO2 by Dyes: A Way to Extend the Range of Photocatalytic Activity of TiO2 to the Visible Region

2018 ◽  
pp. 253-282 ◽  
Author(s):  
Marta I. Litter ◽  
Enrique San Román ◽  
the late María A. Grela ◽  
Jorge M. Meichtry ◽  
Hernán B. Rodríguez
Keyword(s):  
Photocatalytic Activity ◽  
Visible Region

Photocatalytic Degradation of Methylene Blue by NiO Thin Films under Solar Light Irradiation

2019 ◽  
Vol 56 ◽  
pp. 152-157 ◽  
Author(s):  
Abdelouahab Noua ◽  
Hichem Farh ◽  
Rebai Guemini ◽  
Oussama Zaoui ◽  
Tarek Diab Ounis ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Sol Gel ◽  
Visible Region ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Light Irradiation ◽  
Solar Light ◽  
Solar Light Irradiation

Nickel oxide (NiO) thin films were successfully deposited by sol-gel dip-coating method on glass substrates. The structural, morphological and optical properties in addition to the photocatalytic activity of the prepared films were investigated. The results show that the films have a polycrystalline NiO cubic structure with dense NiO grains and average optical transmittance in the visible region. The photocatalytic properties of the films were studied through the degradation of methylene blue and 89% of degradation was achieved for 4.5h of solar light irradiation exposure which indicates the capability of NiO photocatalytic activity.

Hydrothermal Synthesis of Nanosized Titania Photocatalysts Using Novel Water-Soluble Titanium Complexes

2007 ◽  
Vol 124-126 ◽  
pp. 723-726 ◽  
Author(s):  
Makoto Kobayashi ◽  
Koji Tomita ◽  
Valery Petrykin ◽  
Shu Yin ◽  
Tsugio Sato ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Single Phase ◽  
Visible Region ◽  
Water Soluble ◽  
No Oxidation ◽  
Nano Particles ◽  
Titanium Complexes ◽  
Uv Visible

Highly crystalline titania nano-particles were synthesized by hydrothermal method using novel stable water-soluble titanium complexes. It was confirmed that single phase anatase, rutile and brookite, which can be rarely synthesized as a single phase, can be obtained by varying the ligand in the complex and pH of the aqueous solution. TEM observations and BET specific surface area measurements had shown that these samples consisted of nanosized particles of 5~200 nm and had high specific surface areas of 25~150 m2/g. According to UV-visible diffuse reflectance spectra, these titania samples absorbed light in the visible region (λ > 400 nm). Photocatalytic activities in NO oxidation reaction exhibited by synthesized titania powders under the irradiation by UV- visible light were higher than the activity of the commercial TiO2 photocatalyst P25 (Degussa). Especially, under illumination by only visible light of above 510 nm wavelength, photocatalytic activity of the obtained specimens exceeded that of P25 more than four times. We also clearly demonstrated that single phase brookite had high photocatalytic activity for NO oxidation.

Cuprous Oxide Films Deposition by Mid-Frequency Magnetron Sputtering and Their Photocatalytic Activity under Visible Light

NANO ◽  
2021 ◽  
Author(s):  
Z. X. Mu ◽  
H. Li ◽  
X. N. Deng
Keyword(s):  
Photocatalytic Activity ◽  
Magnetron Sputtering ◽  
Visible Light ◽  
Cuprous Oxide ◽  
Deposition Time ◽  
Visible Region ◽  
Mixed Phase ◽  
Photocatalytic Properties ◽  
Oxygen Flow ◽  
Photocatalytic Films

Cuprous oxide (Cu2O) has attracted much attention as a photocatalytic material. In this paper, the mid-frequency reactive magnetron sputtering method was used to prepare Cu2O films on glass slides, and the effects of oxygen flow and deposition time on the structures, morphologies and photocatalytic properties of the films were studied. The results show that the films prepared by this method have smooth surfaces and good absorptivity in the visible region. As the oxygen flow increases, the films transit from the mixed-phase of Cu and Cu2O to the single-phase of Cu2O. When the oxygen flow continues to increase, the films change to a mixed-phase of Cu4O3 and Cu2O. The photocatalytic decolorization of methyl orange under visible light irradiation conditions was used to assess the photocatalytic properties of the prepared films. When the oxygen flow is 6[Formula: see text]sccm and the deposition time is 15[Formula: see text]min, the film exhibits the best photocatalytic activity. Finally, the Mulliken electronegativity theory was used to explain the photocatalytic mechanism of Cu2O. This study confirmed the feasibility of preparing Cu2O photocatalytic films by magnetron sputtering, and provided the experimental basis for the subsequent study of Cu2O photocatalytic films.

scholarly journals SOLVOTHERMAL SYNTHESIS OF BI2WO6 AND ITS PHOTOCATALYTIC ACTIVITY UNDER VISIBLE LIGHT IRRADIATION

2018 ◽  
Vol 54 (4B) ◽  
pp. 42
Author(s):  
Trinh Duy Nguyen
Keyword(s):  
Absorption Spectrum ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Visible Region ◽  
High Photocatalytic Activity ◽  
Light Irradiation ◽  
Different Temperatures

Flower-like Bi2WO6 were successfully synthesized using the solvothermal method at different temperatures and characterized by XRD, FE-SEM, and DRS. We also investigated the photocatalytic activity of Bi2WO6 for the decomposition of rhodamine B under visible light irradiation. From XRD and SEM results, the reaction temperature has significant effects on the morphologies of the samples. From DRS results, Bi2WO6 samples displayed the absorption spectrum up to the visible region and then they showed the high photocatalytic activity under visible light irradiation, as a comparison with TiO2-P25.

scholarly journals Synthesis and Photocatalytic Activity of Mo-Doped TiO2Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-guo Huang ◽  
Xue-ting Guo ◽  
Bo Wang ◽  
Lin-yang Li ◽  
Mei-xia Zhao ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Crystallite Size ◽  
Lattice Distortion ◽  
Visible Region ◽  
Photoelectron Spectra ◽  
Solar Light ◽  
Xenon Lamp ◽  
X Ray ◽  
Mo Doping

The undoped and Mo-doped TiO2nanoparticles were synthesized by sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance UV-visible absorption spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue under irradiation of a 500 W xenon lamp and natural solar light outdoor. Effects of calcination temperatures and Mo doping amounts on crystal phase, crystallite size, lattice distortion, and optical properties were investigated. The results showed that most of Mo6+took the place of Ti4+in the crystal lattice of TiO2, which inhibited the growth of crystallite size, suppressed the transformation from anatase to rutile, and led to lattice distortion of TiO2. Mo doping narrowed the band gap (from 3.05 eV of TiO2to 2.73 eV of TiMo0.02O) and efficiently increased the optical absorption in visible region. Mo doping was shown to be an efficient method for degradation of methylene blue under visible light, especially under solar light. When the calcination temperature was 550°C and the Mo doping amount was 2.0%, the Mo-doped TiO2sample exhibited the highest photocatalytic activity.

scholarly journals Palladium nanoparticles anchored to anatase TiO2 for enhanced surface plasmon resonance-stimulated, visible-light-driven photocatalytic activity

2015 ◽  
Vol 6 ◽  
pp. 428-437 ◽  
Author(s):  
Kah Hon Leong ◽  
Hong Ye Chu ◽  
Shaliza Ibrahim ◽  
Pichiah Saravanan
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Plasmon Resonance ◽  
Visible Light ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Palladium Nanoparticles ◽  
Noble Metals ◽  
Visible Region ◽  
Bet Surface Area

Freely assembled palladium nanoparticles (Pd NPs) on titania (TiO2) nano photocatalysts were successfully synthesized through a photodeposition method using natural sunlight. This synthesized heterogeneous photocatalyst (Pd/TiO2) was characterized through field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET surface area, UV–vis diffuse reflectance spectra (UV-DRS), Raman and photoluminescence (PL) analyses. The simple and smart synthesis anchored well the deposition with controlled Pd NPs size ranging between 17 and 29 nm onto the surface of TiO2. Thus, it gives the characteristic for Pd NPs to absorb light in the visible region obtained through localized surface plasmon resonance (LSPRs). Apparently, the photocatalytic activity of the prepared photocatalysts was evaluated by degrading the endocrine disrupting compound (EDC) amoxicillin (AMX) excited under an artificial visible light source. In the preliminary run, almost complete degradation (97.5%) was achieved in 5 h with 0.5 wt % Pd loading and the degradation followed pseudo-first-order kinetics. The reusability trend proved the photostability of the prepared photocatalysts. Hence, the study provides a new insight about the modification of TiO2 with noble metals in order to enhance the absorption in the visible-light region for superior photocatalytic performance.

Thickness Effect of Zno Film on the Performance of Photocatalytic in a p-Nio/n-Zno Heterostructure under Solar Light Irradiation

2020 ◽  
Vol 62 ◽  
pp. 87-95
Author(s):  
Hichem Farh ◽  
Abdelouahab Noua ◽  
Rebai Guemini ◽  
Djamal Eldine Guitoume ◽  
Oussama Zaoui
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Degradation Rate ◽  
Visible Region ◽  
Light Irradiation ◽  
Thickness Effect ◽  
Solar Light ◽  
Zno Films ◽  
Zno Film ◽  
Solar Light Irradiation

In this work, we studied the ZnO film thickness effect on the photocatalytic performance of n-ZnO/p-NiO heterostructures. The ZnO and NiO films were prepared by sol-gel dip-coating technique and the thickness of the ZnO film was varied by changing the number of coatingsfrom 2 to12. The formation of the p-NiO/n-ZnO heterostructure was confirmed by X ray diffraction (XRD). The obtained ZnO films present a wurtzite structure with a preferred orientation along (002) direction while the NiO film present a cubic structure highly oriented along (200) direction. UV-visible transmittance spectra of the prepared heterostructures revealed a good transparency in the visible region. The photocatalytic propertiesof the n-ZnO/p-NiO heterostructures were investigated by measuring the degradation rate of methylene blue. All the samples exhibit a good photocatalytic activity under solar light irradiation. The photocatalytic activity of p-NiO/n-ZnO heterostructureswas strongly correlated with the number of ZnO coatings. The highest photocatalytic activity was obtained at 6 coatings with a degradation rate of methylene blue equal to 98.67% for 4.5h of irradiation.

Preparation and Enhanced Photocatalytic Activity of AgCl-TiO2 Composite under Simulated Solar Light

2013 ◽  
Vol 807-809 ◽  
pp. 557-561 ◽  
Author(s):  
Wen Tao Yi ◽  
Chun Yan Yan ◽  
Peng Yan ◽  
Shu Yin Liu
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Spectral Response ◽  
Visible Region ◽  
Reaction Model ◽  
Solar Light ◽  
Cubic Phase ◽  
Pseudo First Order Reaction ◽  
Simulated Solar Light ◽  
Bet Analysis

AgCl-TiO2 nanocomposites with a core-shell structure were successfully prepared by hydrothermal treatment. And the products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer Emmett teller (BET) Analysis, and UV-vis diffuse reflectance spectroscopy (DRS). It is found that the composites consist of anatase TiO2 and cubic phase AgCl, which has higher surface area, stronger spectral response in visible region compared with pure TiO2. The photocatalytic activity of these samples was evaluated by photocatalytic decoloration of methyl orange (MO) under simulated solar light. The results show AgCl-TiO2 composite has much higher photocatalytic activity than that of pure TiO2, and it also has very good stability. The kinetic study showed that this photocatalytic process coincided with the Langmuir-Hinshelwood (L-H) pseudo first order reaction model.

Nanocrystal TiO2 Engulfed SiO2-Barium Hexaferrite for Enhanced Electrons Mobility and Solar Harvesting Potential

2015 ◽  
Vol 819 ◽  
pp. 226-231
Author(s):  
Azrina Abd Aziz ◽  
Shaliza Ibrahim ◽  
Saravanan Pichiah
Keyword(s):  
Phase Transformation ◽  
Photocatalytic Activity ◽  
Magnetic Separation ◽  
Sol Gel ◽  
Visible Region ◽  
Barium Hexaferrite ◽  
Band Gap Energy ◽  
Magnetic Core ◽  
Magnetic Photocatalyst ◽  
Titania Photocatalyst

Barium hexaferrite embedded-silica-titania photocatalyst (TiO2-SiO2-BaFe12O19) was synthesized through sol-gel, liquid catalytic phase transformation and solid reaction routes. The magnetic photocatalyst was aimed to harvest the photoenergy from the sunlight, minimize the electron-holes recombination rate, improve the long lifetime charge-carriers transfer to maximize the photocatalytic activity and enhances the separation and reusability of it. The as-synthesized photocatalyst was characterized and the photocatalytic activity was evaluated for the reduction of 2, 4-dichlorophenol (2, 4-DCP) under direct sunlight. The presence of SiO2 interlayer in TiO2-SiO2-BaFe12O19 prevents the phase transformation of magnetic core. TiO2-SiO2-BaFe12O19 benefits the magnetic separation with appreciable magnitude of coercivity (5035.6 Oe) and saturation magnetization (18.8256E-3 emu/g), respectively. The ferrite ions from the magnetic core which dispersed into TiO2 matrix exhibited an evident shift of the absorption in the visible region. This was again confirmed with the reduced band gap energy of 1.90 eV. Furthermore, TiO2-SiO2-BaFe12O19 destructed 100% of 2, 4-DCP compound within 150 min under very bright sunlight with an average irradiance of 820.8 W/m2 (results not shown). The embedding of BaFe12O19 with a SiO2 layer onto TiO2 nanocrystals contributed for an excellent solar-light utilization and ease magnetic separation of the nanosized photocatalyst.

Photocatalytic Degradation of Methylene Blue Using Visible Light Active N-Doped ZnO

2015 ◽  
Vol 1101 ◽  
pp. 299-302 ◽  
Author(s):  
Hanggara Sudrajat ◽  
Sandhya Babel
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Nitrogen Doping ◽  
Spectral Response ◽  
Aqueous Suspension ◽  
Visible Region ◽  
Active Nitrogen ◽  
Visible Light Active ◽  
Doped Zno

A visible light active nitrogen-doped ZnO (N-ZnO) was synthesized using a solvent-free mechanochemical method and applied to degrade methylene blue (MB) dye in aqueous suspension. Results showed that nitrogen doping improved the photocatalytic activity of pristine ZnO by extending its spectral response to visible region. Using 2 g/L of N-ZnO, 98% MB with the initial concentration of 10 mg/L could be degraded within 2 h at pH 7 under 11.3 klux of visible light irradiation. After 6th run, it still exhibited appreciable photocatalytic activity with 94% MB degradation, indicating its high reusability though a simple pretreatment was performed.

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