Photodegradation of Microcystine-LR Uising BiOBr under UV and Visible Light Irradiation

2014 ◽  
Vol 488-489 ◽  
pp. 248-251 ◽  
Author(s):  
Yan Fen Fang ◽  
Xin Yu Li ◽  
Man Ke Jia ◽  
Ying Ping Huang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Layered Structure ◽  
Energy Gap ◽  
Degradation Process ◽  
Light Irradiation ◽  
Reaction Intermediates ◽  
Light Activity ◽  
Degradation Time

BiOBr photocatalyst was prepared by cetyl pyridine bromide (CPB). The characterization of BiOBr was measured by DRS UV-Vis, XRD, BET, TEM/HRTEM, XPS and IR. The energy gap of BiOBr was merely 2.62eV which can absorb visible light (λ473nm), BiOBr was identified to the tetragonal phase exhibits significantly enhanced structural properties and the ration of the amount of Bi and Br on the surface of BiOBr is 1. The BET of BiOBr was 12.03 m2/g and was layered structure. Compared with traditional catalyst TiO2(P25), the prepared BiOBr has good visible light activity and can degradated Microcystine-LR(MC-LR) under UV and Visible light irradation. The degradation time of MC-LR between UV and vis-light irradiation is respectively 60min and 150min under the same condition. It was indicated that the oxidizing rate of O2- in UV system is obviously higher than that of·OH in the vis-light system by ESR experiments, which is also proved in the differences of reaction intermediates in the degradation process under the two lamps.

Preparation and characterization of SiO2/BiOX (X = Cl, Br, I) films with high visible-light activity

RSC Advances ◽  
2015 ◽  
Vol 5 (7) ◽  
pp. 4918-4925 ◽  
Author(s):  
Fan Shen ◽  
Li Zhou ◽  
Jiajia Shi ◽  
Mingyang Xing ◽  
Jinlong Zhang
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Sol Gel ◽  
Layered Structures ◽  
Light Irradiation ◽  
Gel Method ◽  
Light Activity

SiO2/BiOX (X = Cl, Br, I) thin films with layered structures were prepared using a convenient sol–gel method. The films show a high and stable photocatalytic activity under visible-light irradiation.

scholarly journals Synthesis, Analysis, and Testing of BiOBr-Bi2WO6Photocatalytic Heterojunction Semiconductors

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangchao Meng ◽  
Zisheng Zhang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Process ◽  
Light Irradiation ◽  
Enhancement Effect ◽  
Electron Hole ◽  
Experimental Conditions ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Photocatalytic Activities

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

Effect of Water/Acetonitrile Ratio on Dye-Sensitized Photocatalytic H2 Evolution under Visible Light Irradiation

2004 ◽  
Vol 127 (3) ◽  
pp. 413-416 ◽  
Author(s):  
Ryu Abe ◽  
Kazuhiro Sayama ◽  
Hideki Sugihara
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Energy Gap ◽  
Light Irradiation ◽  
Acetonitrile Solution ◽  
H2 Evolution ◽  
Tio2 Photocatalysts ◽  
Dye Sensitized ◽  
Highest Occupied Molecular Orbital ◽  
Splitting System

H 2 production in a water-acetonitrile solution containing iodide as an electron donor was investigated over dye-sensitized Pt∕TiO2 photocatalysts under visible light irradiation, as a potential water-splitting system based on an iodide redox mediator. The rates of H2 evolution decreased with increasing proportion of water in the solutions, because of a decrease in the energy gap between the redox potential of I3−∕I− and the highest occupied molecular orbital levels of the dyes, which decreases the efficiency of electron transfer from I− to dye.

Visible-Light Activity of N-Doped TiO2 Powders and their Applications

2007 ◽  
Vol 544-545 ◽  
pp. 167-170 ◽  
Author(s):  
Wen Bin Cao ◽  
Yi Wei ◽  
Yan Hong Li ◽  
Xiao Ning Zhang
Keyword(s):  
Aqueous Solution ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Guanidine Hydrochloride ◽  
Anatase Tio2 ◽  
Light Irradiation ◽  
Latex Paint ◽  
Doped Tio2 ◽  
Light Activity ◽  
Xrd Patterns

Nitrogen-doped TiO2 has been prepared by calcining technical grade guanidine hydrochloride and commercial anatase TiO2 powders. XRD patterns indicate that the prepared powders are composed of anatase. XPS results show that N atoms have been incorporated into the lattice of anatase. UV-Vis reflectance spectra show that the light absorption of the synthesized N-doped anatase powders has red-shifted well into visible-light region. Degradation of methylene blue (MB) aqueous solution by N-doped anatase has been investigated by UV-Vis light spectrophotometer. The 400-mL 10 mg/L aqueous solution of MB could be degraded with 4 g N-doped TiO2 within 4.5 hrs of visible light irradiation. Photocatalytic paint was prepared by adding the synthesized N-doped nanocrystalline anatase TiO2 powders into self-engineered oxidation resistance latex paint system. The effects of the amount and types of the TiO2 in the paints on the sterilization were systematically investigated. The colony counting method was used to study its sterilization performance under visible light irradiation. The sterilization experiments show that the rate of sterilizing E. coli by the N-doped TiO2 modified paint can exceed more than 99% after irradiation by the visible light for 2 to 4 hours.

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