Maximum SiO2 layer thickness by utilizing polyethylene glycol as the surfactant in synthesis of core/shell structured TiO2–SiO2 nano-composites

Kari, Maryam; Montazeri-Pour, Mehdi; Rajabi, Masoud; Tizjang, Vahide; Moghadas, Shahab

doi:10.1007/s10854-014-2344-x

Cited by 12 publications

(8 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, we presented a novel room-temperature pulsed CVD method of SiO 2 on TiO 2 nanoparticles based on the reaction of SiCl 4 with surface hydroxyl groups to obtain a coating layer with an effective thickness of >3 nm to ensure the suppression of TiO 2 photocatalytic activity . However, SiO 2 coating layers with the thickness of >3 nm may also result in a significant decrease in pigment properties such as lightening power of TiO 2 because the refractive index of SiO 2 (1.46) is much lower than that of anatase TiO 2 (2.55). ,, …”

Section: Introductionmentioning

confidence: 99%

“…34 However, SiO 2 coating layers with the thickness of >3 nm may also result in a significant decrease in pigment properties such as lightening power of TiO 2 because the refractive index of SiO 2 (1.46) is much lower than that of anatase TiO 2 (2.55). 10,35,36 SnO 2 has attracted increasing attention due to its high transparency (within the 0.4−1.2 μm range), high thermal and chemical stability, and excellent optical and electrical proper- ties. 37,38 In addition, the refractive index of SnO 2 (2.00) is similar to that of TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Suppression of TiO₂ Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO₂ Protective Layer

Zhu

Guo

et al. 2018

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

TiO 2 pigments are widely used in paint industries. Inert coating layers were usually deposited on the TiO 2 pigments to suppress the photocatalytic activity of TiO 2 , which can prevent the degradation of surrounding polymer molecules. However, the traditional wet chemical methods normally form thick films, which would impair the pigment properties of TiO 2 . In this work, SnO 2 and SiO 2 protective layers were grown on the TiO 2 particle surface by lowtemperature pulsed chemical vapor deposition. At temperatures <60 °C, thin and uniform amorphous SnO 2 films were obtained. The photocatalytic activities of both TiO 2 /SnO 2 and TiO 2 /SiO 2 core−shell particles were suppressed, and TiO 2 /SnO 2 core− shell particles showed higher lightening power than TiO 2 /SiO 2 . According to transient fluorescence, photocurrent, and electrochemical impedance spectroscopy measurements, the low electron mobility of amorphous SnO 2 and SiO 2 films led to fast recombination of photogenerated electrons and holes, thus preventing their migration to the surface and suppressing the photocatalytic activity of TiO 2 .

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Suppression of TiO₂ Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO₂ Protective Layer

Zhu

Guo

et al. 2018

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…By examination of absorption changes at the maximum wavelength, the destruction percentage of methylene blue dye was obtained using the following equation [38]:…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization and Comparison of Photo-catalytic Efficiency of Fe3O4/SiO2/TiO2, SrFe12O19/SiO2/TiO2 and Fe3O4/SiO2/ZnO Core/shell/shell Nano-structures

Bavarsiha¹,

Dadashian²,

Montazeri-Pour³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

In this research work, three magnetic composites of Fe3O4/SiO2/TiO2, SrFe12O19/SiO2/TiO2 and Fe3O4/SiO2/ZnO with core/shell/shell structures were successfully prepared by the sol-gel method. For this purpose, in the first step, soft magnetic and hard magnetic powders of Fe3O4 and SrFe12O19 were synthesized using carbon reduction and co-precipitation routes, respectively. In the second step, silica coating was performed by controlling the hydrolysis and condensation of the tetraethyl orthosilicate (TEOS) precursor on the magnetic cores. In the third step, a coating of TiO2 or ZnO photo-catalytic shells was made on as-prepared composites using precursors of titanium n-butoxide (TNBT) or zinc nitrate hexahydrate, respectively. The as-prepared magnetically separable photo-catalysts were characterized using XRD, FESEM, TEM and VSM. The results of the FESEM and TEM analyses confirmed the formation of the core/shell/shell structures. The saturation magnetization of the Fe3O4/SiO2/TiO2, SrFe12O19/SiO2/TiO2 and Fe3O4/SiO2/ZnO photo-catalytic materials was 41.5 emu/g, 33 emu/g and 49 emu/g, respectively. Evaluation of the photo-catalytic activity of Fe3O4/SiO2/TiO2, SrFe12O19/SiO2/TiO2 and Fe3O4/SiO2/ZnO composites by using methylene blue (MB) shows degradation percentages of 84%, 80% and 58%, respectively, under UV illumination.

show abstract

“…Furthermore, the frequency of Fe III -O band (Fe III O 6 ) shows a shift in comparison with Fe-O absorption band in Fe 3 O 4 bulk (570 cm -1 ) which is due to the increase in the surface band force constant originated from the refinement of grains to nano scale [47,48]. The bands centered at 2923 cm -1 and 1624 cm -1 are related to bending vibrations of H-O-H of water molecules [49,50], whilst the band at 3390 cm -1 is attributed to the tensile vibration of O-H group [25,50,51]. According to the FTIR spectrum of F20/TS nanocomposite sample, absorption at low frequencies of 500-900 cm -1 is associated with the tensile vibration of Ti-O-Ti bonds [10].…”

Section: Resultsmentioning

confidence: 99%

Comparison of the structural and photo-catalytic properties of nanostructured Fe3O4/TiO2 core-shell composites synthesized by ultrasonic and Stöber methods

et al. 2020

Self Cite

View full text Add to dashboard Cite

In the present research, Fe3O4/TiO2 magnetic photo-catalytic nanocomposites with a core/shell structure were successfully synthesized using two techniques of ultrasonic and St?ber. In this way, iron oxide (II, III) nanoparticles as soft magnetic cores of this composite were prepared by utilizing a chemical method assisted by ultrasound with a Fe+3/Fe+2 molar ratio of 1.5 under the nitrogen atmosphere. Thereafter, titanium oxide coating was performed on Fe3O4 nanoparticles by using tetrabutyl orthotitanate (TBOT) and titanium isopropoxide (TTIP) precursors. The resultant nanostructures were characterized by means of X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, energy dispersive X-ray (EDX) analysis, vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Through findings obtained from TEM examinations, the formation of core/shell nanostructure was confirmed in the prepared Fe3O4/TiO2 composites. Analysis of magnetic properties revealed that titanium oxide coating on iron oxide nanoparticles reduces saturation magnetization (Ms). The values of saturation magnetization for Fe3O4 powder and Fe3O4/TiO2 nanocomposite powders achieved via ultrasonic and St?ber methods were 60, 23 and 9 emu/g, respectively. Photo-catalytic properties of Fe3O4/TiO2 nanostructures were evaluated by the use of methylene blue dye under UV light. Results indicated that Fe3O4/TiO2 composite obtained by the St?ber method has a better photo-catalytic property as well as a decreased but acceptable magnetic separation. Degradation of methylene blue dye in the presence of photo-catalytic powder prepared by ultrasonic and St?ber procedures was 61 and 69 %, respectively, within 90 minutes of UV light exposure.

show abstract

Maximum SiO2 layer thickness by utilizing polyethylene glycol as the surfactant in synthesis of core/shell structured TiO2–SiO2 nano-composites

Cited by 12 publications

References 30 publications

Suppression of TiO₂ Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO₂ Protective Layer

Suppression of TiO₂ Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO₂ Protective Layer

Synthesis, Characterization and Comparison of Photo-catalytic Efficiency of Fe3O4/SiO2/TiO2, SrFe12O19/SiO2/TiO2 and Fe3O4/SiO2/ZnO Core/shell/shell Nano-structures

Comparison of the structural and photo-catalytic properties of nanostructured Fe3O4/TiO2 core-shell composites synthesized by ultrasonic and Stöber methods

Contact Info

Product

Resources

About

Maximum SiO2 layer thickness by utilizing polyethylene glycol as the surfactant in synthesis of core/shell structured TiO2–SiO2 nano-composites

Cited by 12 publications

References 30 publications

Suppression of TiO2 Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO2 Protective Layer

Suppression of TiO2 Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO2 Protective Layer

Synthesis, Characterization and Comparison of Photo-catalytic Efficiency of Fe3O4/SiO2/TiO2, SrFe12O19/SiO2/TiO2 and Fe3O4/SiO2/ZnO Core/shell/shell Nano-structures

Comparison of the structural and photo-catalytic properties of nanostructured Fe3O4/TiO2 core-shell composites synthesized by ultrasonic and Stöber methods

Contact Info

Product

Resources

About

Suppression of TiO₂ Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO₂ Protective Layer

Suppression of TiO₂ Photocatalytic Activity by Low-Temperature Pulsed CVD-Grown SnO₂ Protective Layer