Magnetically separable Fe3O4@SiO2@TiO2-Ag microspheres with well-designed nanostructure and enhanced photocatalytic activity

Chi, Yuanying; Yuan, Qing; Li, Yanjuan; Zhao, Liang; Li, Nan; Li, Xiaotian; Yan, Wenfu

doi:10.1016/j.jhazmat.2013.08.077

Cited by 145 publications

(49 citation statements)

References 37 publications

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“…22-1086. The broad diffraction peak at 2θ = 15-25 • corresponds to an amorphous silica layer in the nanocomposite structure [32,33]. The diffraction peaks of TiO 2 can be attributed to The magnetic properties of uncoated and coated ferrite nanocomposites were investigated using magnetic hysteresis curves from ACMS analysis at room temperature as shown in Figure 6.…”

Section: Characterization Of the Nanoparticlesmentioning

confidence: 99%

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

et al. 2017

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Core-interlayer-shell Fe 3 O 4 /SiO 2 /TiO 2 , CoFe 2 O 4 /SiO 2 /TiO 2 and BaFe 12 O 19 /SiO 2 /TiO 2 magnetic photocatalysts were obtained. A water-in-oil microemulsion system with suitable surfactants was used for functionalization of the magnetic core with silica interlayer and TiO 2 -based photocatalyst. Uncoated and coated particles were characterized by electrophoretic measurements, X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) measurements, diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometer (VSM) analysis. The pH of the solution and corresponding zeta potential was found to be essential for appropriate formation of ferrite core/silica interlayer/TiO 2 shell nanocomposite, since the electrical charge controls interactions during functionalization of the magnetic core particles. Thus, the development of multilayer structure in the isoelectric point (IEP) region enhanced adhesion of ferrite, silica and titania particles. The obtained Fe 3 O 4 /SiO 2 /TiO 2 , CoFe 2 O 4 /SiO 2 /TiO 2 and BaFe 12 O 19 /SiO 2 /TiO 2 nanocomposites revealed superparamagnetic behavior. The decomposition rate of phenol and carbamazepine allowed to estimate their photocatalytic activity. Progress of photocatalytic mineralization of organic compounds was evaluated by total organic carbon (TOC) measurements. Photocatalytic activity measured in four subsequent cycles showed good reusability as no loss of efficiency of phenol degradation was observed.

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Section: Characterization Of the Nanoparticlesmentioning

confidence: 99%

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

et al. 2017

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“…63 We anticipate that for thermoliable substrates (such as chiral compounds) much lower reaction rates are expected as the temperature should be reduced far below 150 o C. Yet, the overall production rate can be kept similar by incresing the catalyst loading in the reactor. The current method allows fast and reproducible preparation of larger amounts of composite catalysts in a very reproducible way.…”

Section: Catalytic Activity and Stabilitymentioning

confidence: 99%

“…These data indicate that in case of a very thin catalyst shell there exists an interaction between the NiFe2O4 core and titania shell, which is detrimental for catalytic activity. A possible cause is the electronic interaction between TiO2 and ferrite referred to as photodissolution phenomenon, which was extensively reported in literature [61][62][63][64] . When the thickness of titania shell increases, this detrimental effect becomes less pronounced as the relative contribution from the area near the core-shell interface decreases as compared to the total available surface area.…”

Section: Catalytic Activity and Stabilitymentioning

confidence: 99%

Direct amide synthesis over core–shell TiO₂@NiFe₂O₄ catalysts in a continuous flow radiofrequency-heated reactor

et al. 2016

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A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. AbstractCore-shell composite magnetic catalysts TiO2@NiFe2O4 with a titania loading of 9-32 wt. % have been synthesised by sol-gel method for direct amide synthesis in a radiofrequency (RF)-heated continuous flow reactor. The catalyst calcination temperature was optimised in the range of 350-500 ºC and the highest activity was observed for the catalyst calcined at 500 ºC due to conversion of titania into catalytically active anatase phase. No reaction between the magnetic core and the titania shell was observed up to the calcination temperature of 1000 ºC and no sintering of titania shell was observed after calcination at 500 ºC. The comparison of direct amide synthesis in a continuous flow fixed bed reactor under conventional and RF heating demonstrated that the RF heating mode increased the apparent reaction rate by 60 % and decreased the deactivation rate due to a better temperature uniformity. The titania weight normalised reaction rate in the RF-heated reactor was constant for titania loadings above 17 wt. %, while it decreased by a factor of 3 at lower titania loadings because of interactions between the ferrite core on the thin layer of the catalyst. The catalyst deactivation study showed that the deactivation rate could be accurately described by a first order kinetics and that the main reason of deactivation was coking. The catalyst regeneration via calcination at 400 ºC resulted in the catalyst sintering, while a treatment with a hydrogen peroxide solution at 90 ºC fully recovered catalytic activity.

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“…Several modifications have been employed for improving the charge separation efficiency of TiO 2 such as doping titania with noble metals [4,5], metal ions [6][7][8] or incorporation of other semiconductor metal oxide [9]. The incorporating metal ions into TiO 2 is considered an efficient approach for acquiring an improved photocatalyst by introducing intermediate impurity energy levels, allowing the CB electrons to flow to noble metals and escape from recombination [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Effect of duty cycle and electrolyte additive on photocatalytic performance of TiO2-ZrO2 composite layers prepared on CP Ti by micro arc oxidation method

Babaei

Dehghanian

Taheri

et al. 2016

Surface and Coatings Technology

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The aim of this work is to discuss the photocatalytic performance of the titania-zirconia porous photocatalyst layers synthesized via micro arc oxidation technique. An attempt was also made to put forward the basic formation mechanism of the layers. Impedance and optical properties of the photocatalyst layers were studied by electrochemical impedance spectroscopy (EIS), Photoluminescence spectroscopy and UV-vis absorption spectroscopy, in order to assess their intrinsic catalytic properties.The results of the EIS were correlated with the microstructural characteristics along with measurements of Methylene Blue (MB) photocatalytic degradation. The results show enhanced photocatalytic activity of TiO 2 -ZrO 2 composite layers compared to pure TiO 2 layer. It was revealed that the photocatalytic activity of the layers prepared at different duty cycles is influenced by characteristics of microdischarge regime imposed by working electrolytes with varying additive concentration. The results of photocatalytic degradation of methylene blue were in good agreement with those obtained from electrochemical analysis.

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Magnetically separable Fe3O4@SiO2@TiO2-Ag microspheres with well-designed nanostructure and enhanced photocatalytic activity

Cited by 145 publications

References 37 publications

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

Direct amide synthesis over core–shell TiO₂@NiFe₂O₄ catalysts in a continuous flow radiofrequency-heated reactor

Effect of duty cycle and electrolyte additive on photocatalytic performance of TiO2-ZrO2 composite layers prepared on CP Ti by micro arc oxidation method

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Magnetically separable Fe3O4@SiO2@TiO2-Ag microspheres with well-designed nanostructure and enhanced photocatalytic activity

Cited by 145 publications

References 37 publications

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

Direct amide synthesis over core–shell TiO2@NiFe2O4 catalysts in a continuous flow radiofrequency-heated reactor

Effect of duty cycle and electrolyte additive on photocatalytic performance of TiO2-ZrO2 composite layers prepared on CP Ti by micro arc oxidation method

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Direct amide synthesis over core–shell TiO₂@NiFe₂O₄ catalysts in a continuous flow radiofrequency-heated reactor