In-situ manganese doping of TiO2 nanostructures via single-step electrochemical anodizing of titanium in an electrolyte containing potassium permanganate: A good visible-light photocatalyst

Momeni, Mohamad Mohsen; Hakimian, M.; Kazempour, Ali

doi:10.1016/j.ceramint.2015.07.158

Cited by 101 publications

(29 citation statements)

References 33 publications

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“…An improvement of the photocatalytic activity can be achieved if more photo‐generated electrons and holes move to the surface of the semiconductor particles before they recombine in bulk. The doping of TiO 2 with transition metals can introduce electron capture centres that result in a decrease of electron–hole recombination centres . The photocatalytic activity of TiO 2 and TiO 2 ‐SiO 2 photocatalysts is improved if Pt, Pd, Au or Ag are used as dopants or if Pt, Pd, Au or Ag are deposited on TiO 2 but these metals are rare and expensive.…”

Section: Introductionmentioning

confidence: 99%

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO₂‐SiO₂ Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

et al. 2018

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The objective of this research is to examine how Cu modification can improve the photocatalytic activity of TiO2‐SiO2, to explain the correlation between the Cu concentration and the chemical state of Cu cations in the TiO2‐SiO2 matrix, and the photocatalytic activity under UV/solar irradiation. The Cu‐modified TiO2‐SiO2 photocatalysts were prepared by a low‐temperature sol–gel method from organic Cu, Si and Ti precursors with various Cu concentrations (0.05–3 mol %). The sol–gels were dried at 150 °C to obtain the photocatalysts in a powder form. The photocatalytic activity was determined by using a fluorescence‐based method of terephthalic acid decomposition. An up to three times increase in photocatalytic activity is obtained if the TiO2‐SiO2 matrix is modified with Cu in a narrow concentration range from 0.05 to 0.1 mol %. At higher Cu loadings, the photocatalytic activity of the Cu‐modified photocatalysts is lower than that of the un‐modified reference TiO2‐SiO2 photocatalyst. XRD was used to show that all Cu‐modified TiO2‐SiO2 composites with different Cu concentrations have the same crystalline structure as un‐modified TiO2‐SiO2 composites. The addition of Cu does not change the relative ratio between the anatase and brookite phases or unit cell parameters of the two TiO2 crystalline structures. We used Cu K‐edge X‐ray absorption near edge structure and extended X‐ray absorption fine structure analyses to determine the valence state and local structure of Cu cations in the Cu‐modified TiO2‐SiO2 photocatalysts. The results elucidate the mechanism responsible for the improved photocatalytic activity. In samples with a low Cu content, which exhibit the highest activity, Cu−O−Ti connections are formed, which suggests that the activity enhancement is caused by the attachment of CuII cations on the surface of the photocatalytically active TiO2 nanoparticles, so CuII cations may act as free‐electron traps, which reduce the intensity of recombination between electrons and holes at the TiO2 photocatalyst surface. At higher Cu loadings no additional Cu−O−Ti connections are formed, instead only Cu−O−Cu connections are established. This indicates the formation of amorphous or nanocrystalline copper oxide, which hinders the photocatalytic activity of TiO2.

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Section: Introductionmentioning

confidence: 99%

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO₂‐SiO₂ Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

et al. 2018

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“…This is one of the most important drawbacks of TiO 2 which limits its practical applications. Hence, shifting TiO 2 sensitivity to the visible range will significantly increase its photocatalytic efficiency …”

Section: Introductionmentioning

confidence: 99%

Individual and interaction effects of operating parameters on the photocatalytic degradation under visible light illumination: Response surface methodological approach

et al. 2017

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In this study, for the first time a statistical analysis based on the response surface methodology (RSM) was employed to investigate individual and interaction effects of key operating parameters of the photocatalytic degradation under visible-light irradiation using Ag-S/PEG/TiO 2 . Ag-S/PEG/ TiO 2 is a visible-light-driven photocatalyst and was synthesized (based on earlier research) by co-doping of TiO 2 with silver and sulphur and addition of polyethylene glycol (as a reagent template). In addition, the model pollutant was methylene orange (MO) and the studied operating parameters included the photocatalyst loading, initial concentration of the pollutant, and pH of the solution. The statistics-based experimental design and RSM was utilized to find a quadratic model as a functional relationship between the degradation efficiency and the three operating parameters. The regression analysis with R 2 value of 0.9678 showed a close fit between the model prediction and experimental data of the degradation efficiency. The analysis of variance based on the model indicated that pH of the solution was the most influential factor, while the two other operating parameters were also significant. The efficiency of MO degradation reached 94.0 % under the optimum conditions (i.e. photocatalyst loading of 1.20 g/L, MO concentration of 5 mg/L, and pH of 2).

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“…It has been reported TiO 2 nanotubes will show superior photo-catalytic and photo-electronic performance over TiO 2 nanoparticles because of their large specific surface area [29][30][31][32][33][34][35]. Similarly, the large specific surface area also has influence on luminescence of phosphors since the surface area can influence on the photo-electronic performance.…”

Section: Introductionmentioning

confidence: 99%

Controllable synthesis and luminescence of YPO4:Ln3+ (Ln = Eu and Sm) nanotubes

Sun

2016

J Mater Sci: Mater Electron

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YPO 4 :Ln 3? (Ln = Eu and Sm) nanotubes were synthesized by a precipitation process in the presence of SDS. The XRD results showed that all samples have a xenotime type tetragonal structure, indicating that doped rare earth ions have no influence on the phase. The SEM and TEM images showed that all samples are nanotubes. On basis of the morphology of samples and the properties of SDS, the possible formation mechanism was speculated. YPO 4 :Eu 3? and YPO 4 :Sm 3? nanotubes showed characteristic emission bands of Eu 3? and Sm 3? ions, respectively. For YPO 4 :Eu 3? /Sm 3? nanotubes, the codoping Sm 3? ions can enhance the emission intensity of Eu 3? ions.

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In-situ manganese doping of TiO2 nanostructures via single-step electrochemical anodizing of titanium in an electrolyte containing potassium permanganate: A good visible-light photocatalyst

Cited by 101 publications

References 33 publications

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO₂‐SiO₂ Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO₂‐SiO₂ Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

Individual and interaction effects of operating parameters on the photocatalytic degradation under visible light illumination: Response surface methodological approach

Controllable synthesis and luminescence of YPO4:Ln3+ (Ln = Eu and Sm) nanotubes

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In-situ manganese doping of TiO2 nanostructures via single-step electrochemical anodizing of titanium in an electrolyte containing potassium permanganate: A good visible-light photocatalyst

Cited by 101 publications

References 33 publications

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO2‐SiO2 Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO2‐SiO2 Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

Individual and interaction effects of operating parameters on the photocatalytic degradation under visible light illumination: Response surface methodological approach

Controllable synthesis and luminescence of YPO4:Ln3+ (Ln = Eu and Sm) nanotubes

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Effects of Different Copper Loadings on the Photocatalytic Activity of TiO₂‐SiO₂ Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water

Effects of Different Copper Loadings on the Photocatalytic Activity of TiO₂‐SiO₂ Prepared at a Low Temperature for the Oxidation of Organic Pollutants in Water