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

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.

2018 ◽  
Vol 42 (13) ◽  
pp. 11109-11116 ◽  
Author(s):  
R. Salimi ◽  
A. A. Sabbagh Alvani ◽  
N. Naseri ◽  
S. F. Du ◽  
D. Poelman

A new plasmonic Ag hybridized CuWO4/WO3 heterostructured nanocomposite was successfully synthesized via a ligand-assisted sol gel method and the photocatalytic activity was evaluated by photo-degradation of methylene blue (MB) under visible light irradiation.


2018 ◽  
Vol 5 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Abdurrashid Haruna ◽  
Ibrahim Abdulkadir ◽  
Suleiman Ola Idris

Perovskite-like BiFeO3 nanoparticles doped with barium and sodium ions were synthesized via the citric acid route by the sol-gel method. The as-prepared Bi0.65Na0.2Ba0.15FeO3 nanopowders were divided into three equal portions and separately annealed at various annealing temperatures of 600, 700 and 800°C. The powders were characterized using X-ray diffraction (XRD) and crystallized with a rhombohedral R3c space group. Scanning electron microscopy was used to determine the morphology of the crystal and Fourier transform infrared spectroscopy was conducted at room temperature to determine the phase purity and the B-site formation in the perovskite structure. The UV-vis diffuse reflectance spectroscopy of all the materials was investigated, showing strong photoabsorption (λ > 420 nm). The doping effect of BiFeO3 enhanced photocatalytic activity while it significantly reduced the energy bandgap to 2.05 eV (for BNBFO at 800°C) which showed strong visible light absorption. The photocatalytic activity of Bi0.65Na0.2Ba0.15FeO3 nanomaterials was tested by monitoring the degradation rate of methylene blue dye pollutant under visible light irradiation in aqueous solution. All powders showed photoactivity after 2 hours of visible light irradiation. The annealing temperature greatly affected the methylene blue degradation, showing the efficiencies of 57, 67 and 75 % for BNBFO at 600, 700 and 800°C, respectively. Kinetic studies were carried out and the rate constants of 6.70 x 10-3, 8.90 x 10-3 and 1.05 x 10-2 min-1 were obtained for powders annealed at 600, 700 and 800°C, respectively. The photocatalytic mechanism of the degradation process was proposed in this study.


2019 ◽  
Vol 10 ◽  
pp. 1412-1422 ◽  
Author(s):  
Minlin Ao ◽  
Kun Liu ◽  
Xuekun Tang ◽  
Zishun Li ◽  
Qian Peng ◽  
...  

A BiOCl/TiO2/diatomite (BTD) composite was synthesized via a modified sol–gel method and precipitation/calcination method for application as a photocatalyst and shows promise for degradation of organic pollutants in wastewater upon visible-light irradiation. In the composite, diatomite was used as a carrier to support a layer of titanium dioxide (TiO2) nanoparticles and bismuth oxychloride (BiOCl) nanosheets. The results show that TiO2 nanoparticles and BiOCl nanosheets uniformly cover the surface of diatomite and bring TiO2 and BiOCl into close proximity. Rhodamine B was used as the target degradation product and visible light (λ > 400 nm) was used as the light source for the evaluation of the photocatalytic properties of the prepared BTD composite. The results show that the catalytic performance of the BTD composite under visible-light irradiation is much higher than that of TiO2 or BiOCl alone. When the molar ratio of BiOCl to TiO2 is 1:1 and the calcination temperature is 400 °C, the composite was found to exhibit the best catalytic effect. Through the study of the photocatalytic mechanism, it is shown that the strong visible-light photocatalytic activity of the BTD composite results mainly from the quick migration of photoelectrons from the conduction band of TiO2/diatomite to the surface of BiOCl, which promotes the separation effect and reduces the recombination rate of the photoelectron–hole pair. Due to the excellent catalytic performance, the BTD composite shows great potential for wide application in the field of sewage treatment driven by solar energy.


2008 ◽  
Vol 8 (5) ◽  
pp. 2699-2702 ◽  
Author(s):  
K. S. Yao ◽  
D. Y. Wang ◽  
C. Y. Chang ◽  
W. Y. Ho ◽  
L. Y. Yang

In this study, a novel porphyrin dye, 5, 10, 15, 20-tetraphenyl-21H, 23H-porphine nickel (TPPN) doped TiO2 (TiO2/TPPN) thin film with visible light respondency was prepared using a sol–gel method and characterized with XRD, SEM, UV-Vis instruments. The observation showed that the absorption edge of TPPN dye-doped thin film shifted into the visible light region. The photocatalytic indigo carmine degradation results showed that under visible light irradiation (λ > 400 nm) for 6 hrs, the photocatalytic activity of TiO2 thin film sensitized with 200 μM of TPPN dye showed the best performance, with an indigo degradation ratio up to 96%. Moreover, the TiO2/TPPN thin film showed a relevant photocatalytic bactericidal effect on Erwinia carotovora subsp. carotovora 7 induced vegetable soft rot disease in the visible spectral region. Evidence for the photocatalytic disinfection technique against a plant pathogen under visible light irradiation will have potential for direct application in future control of plant diseases in irrigation water systems.


RSC Advances ◽  
2015 ◽  
Vol 5 (92) ◽  
pp. 75474-75482 ◽  
Author(s):  
F. Mahdizadeh ◽  
S. Aber

ZnO and CuO thin films were synthesized by a sol–gel and direct crystallization method on granular porous natural scoria respectively and CuO/ZnO/scoria was used for water treatment under visible light irradiation.


2015 ◽  
Vol 14 (3) ◽  
pp. 536-542 ◽  
Author(s):  
J. J. Macías-Sánchez ◽  
L. Hinojosa-Reyes ◽  
A. Caballero-Quintero ◽  
W. de la Cruz ◽  
E. Ruiz-Ruiz ◽  
...  

The photocatalytic performance of modified 30% wt. N-ZnO nanoparticles under visible light irradiation was demonstrated by the oxidation of picloram and 2,4-D.


Here, we reported a modern sort of zinc sulfide thin films as a catalyst was prepared from simple sol-gel approach. The as-deposited samples were further annealed at 200, 300, 4000 C temperatures under atmospheric environment. The variation in the annealing temperature becomes crucial for optimizing the prepared samples characterization and dye degradation behavior. Structural and morphological analysis recommends that test were hexagonal crystal structure and spherical shaped morphology, particle size was found within the range of 25-40 nm. The significant red shift was found within the absorption edge and lessening of energy in the band gap was found whereas the annealing temperature is increased from 200 to 400 oC. Recombination of photo-generated electron-hole sets was moreover distinguished and the photo-degradation test was monitored methylene blue dye solutions under visible light irradiation. The 400 oC annealed sample showed superior photocatalytic performance such as high degradation efficiency and long term stability towards MB dye.


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