Photocatalytic Degradation of Methyl Orange: Influence of H2O2 in the TiO2-Based System

2008 ◽  
Vol 8 (2) ◽  
pp. 728-732 ◽  
Author(s):  
Luminita Andronic ◽  
Simona Manolache ◽  
Anca Duta

The purpose of this study was to investigate the photocatalytic oxidation of a reactive azo dye. The photocatalytic activity of the TiO2 was studied using a reactor equipped with UV-A sources, with maximum emission at 365 nm. The photocatalytic activity of the TiO2 powder (99.9% anatase) and thin films has been measured through the decomposition of methyl orange solutions. The thin film was prepared by doctor blade and spray pyrolysis deposition (SPD). The TiO2 suspensions were prepared at 1 g/L concentration, and the initial methyl orange concentration was fixed at 7.8125 mg/L. The influence of the TiO2 (powder or thin films) and/or O2 and H2O2 on the photobleaching rate, was tested under different experiments, at pH = 5. Thin films (doctor blade) of TiO2 formed of mezo-sized aggregates formed of nanosized anatase crystallites show better photobleaching efficiency than thin film(SPD) due to their large internal surface. The rate is even higher in H2O2 compared to oxygen environment.

2013 ◽  
Vol 341-342 ◽  
pp. 191-194
Author(s):  
Hua Nan Guan

Nanosized WO3-doped TiO2 photocatalysts were synthesized by a simple hydrothermal method, and characterized by scanning electron microscopy (SEM) and BET surface area analyzer. The photocatalytic activity of undoped TiO2 and WO3 doped TiO2 photocatalysts was evaluated by the photocatalytic oxidation degradation of methyl orange in aqueous solution. The results show that the photocatalytic activity of the WO3 doped TiO2 photocatalyst is much higher than that of undoped TiO2.


2015 ◽  
Vol 18 (2) ◽  
pp. 121-131
Author(s):  
Khoa Tien Le ◽  
Ngoc Chau Hoang ◽  
Tien Thuy Thai ◽  
Anh Trung Le ◽  
Thinh Nguyen Huu Pham ◽  
...  

TiO2 P25 was fluorinated by thermal shock method in order to study the influence of thermal shock fluorination on the surface properties and the photocatalytic activity for the degradation of cationic and anionic organic dyes at different pH values. The surface charge of catalysts was characterized by the pHPZC measurement. The photocatalytic activity of catalysts was evaluated via the degradation of methylene blue (cationic dye) and methyl orange (anionic dye). The results showed that the thermal shock fluorination and the rise of solution pH can increase the surface negative charge of TiO2, which enhanced the adsorption of methylene blue and then improved the photocatalytic degradation of this cationic dye under UV and visible light. On the other hand, after the fluorination, the adsorption of methyl orange on TiO2 was strongly reduced, which limited the photocatalytic oxidation of this anion dye.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
J. Santos Cruz ◽  
S. A. Mayén Hernández ◽  
F. Paraguay Delgado ◽  
O. Zelaya Angel ◽  
R. Castanedo Pérez ◽  
...  

Effects on the optical, electrical, and photocatalytic properties of undoped CuS thin films nanodisks vacuum annealed at different temperatures were investigated. The chemical bath prepared CuS thin films were obtained at 40°C on glass substrates. The grain size of13.5±3.5 nm was computed directly from high-resolution transmission electron microscopy (HRTEM) images. The electrical properties were measured by means of both Hall effect at room temperature and dark resistivity as a function of the absolute temperature 100–330 K. The activation energy values were calculated as 0.007, 0.013, and 0.013 eV for 100, 150, and 200°C, respectively. The energy band gap of the films varied in the range of 1.98 up to 2.34 eV. The photocatalytic activity of the CuS thin film was evaluated by employing the degradation of aqueous methylene blue solution in the presence of hydrogen peroxide. The CuS sample thin film annealed in vacuum at 150°C exhibited the highest photocatalytic activity in presence of hydrogen peroxide.


2017 ◽  
Vol 28 (15) ◽  
pp. 11002-11011 ◽  
Author(s):  
G. V. Khade ◽  
N. L. Gavade ◽  
M. B. Suwarnkar ◽  
M. J. Dhanavade ◽  
K. D. Sonawane ◽  
...  

2011 ◽  
Vol 239-242 ◽  
pp. 1850-1853
Author(s):  
Shu Kai Zheng

A series of TiO2 thin films with and without Ce3+ doping were successfully obtained on microscope glass slides by sol-gel method. The photocatalytic activities of the pure TiO2 and Ce3+-doped TiO2 thin films were evaluated by the degradation of rhodamine B solution. The effects of both Ce3+ contents and annealing temperatures on the photocatalytic activities of the samples were examined. The results indicated that the TiO2 thin film with an atomic ratio of Ti:Ce=5:1 annealed at 300°C had a higher photocatalytic activity among the samples.


2007 ◽  
Vol 336-338 ◽  
pp. 2189-2192
Author(s):  
Lei Ge ◽  
Ming Xia Xu ◽  
Hai Bo Fang ◽  
Ming Sun

Nano anatase TiO2 thin films on glass slide substrates were prepared via a dip-coating method using refluxed sols (RS) as precursors, then dried under infrared light and calcined at 500°C for 30min. The RS sols and TiO2 films were characterized by FT-IR, XRD, TEM, UV-Vis and SEM. The photocatalytic activities of the film samples were tested by the degradation of methyl orange solution with a concentration of 10mg/L under UV light irradiation. The results reveal that the RS sols are flavescent, alkalescent and contain needle-like anatase crystals. The TiO2 films are uniform, compact and transparent, their maximal light transmittance exceed 80% under visible light region. The degradation of methyl orange results illustrate that the RS-6 TiO2 thin films show the best photocatalytic activities, the decoloration rate of the methyl orange solution with RS-6 TiO2 thin films reachs 99% after irradiated 160min under UV light.


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