Thermal behaviour of the TiO2-based gels obtained by microwave-assisted sol–gel method

Stanciu, Irina; Predoană, Luminița; Cusu, Jeanina Pandele; Preda, Silviu; Anastasescu, Mihai; Vojisavljević, Katarina; Malič, Barbara; Zaharescu, Maria

doi:10.1007/s10973-017-6478-y

Cited by 11 publications

(10 citation statements)

References 31 publications

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“…In the case of MW treated samples, more decomposition steps were observed. A similar behavior was observed in the case of V-doped TiO 2 gels obtained by MWassisted sol-gel method [32]. The results are in agreement with the FT-IR results that also identified more vibration bands for the samples obtained by MW sol-gel method.…”

Section: Resultssupporting

confidence: 89%

Comparative study of the thermal behavior of Sr–Cu–O gels obtained by sol–gel and microwave-assisted sol–gel method

Predoană

Atkinson

Karaj

et al. 2020

J Therm Anal Calorim

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In the literature data, several papers reported the synthesis by various chemical or physical methods of the SrCu 2 O 2 (SCO) having possible applications in thermoelectric or completely electronic devices such as solar cells, liquid crystal displays and touch screen. A great challenge is represented by the formation of the pure SrCu 2 O 2 (SCO), due to the high labiality of the Cu valence, depending on temperature. In the present paper, the thermal behavior of Sr-Cu-O gels obtained by sol-gel (SG) or microwave (MW)-assisted SG methods was studied in order to establish the appropriate thermal conditions for pure nanostructured SrCu 2 O 2 preparation. As reagents, copper and strontium acetylacetonate in alcoholic media were used. The starting solutions were homogenized either by stirring for 2 h at room temperature or were exposed to MW for 5 min at 300 W and a frequency of 2.45 GHz. Both solutions were left to gel at room temperature. The obtained gels were investigated by scanning electron microscopy, Fourier-transform infrared spectroscopy, as well as by thermal analysis combined with evolved gas analysis (TG/DTA-MS) measurements in air, inert and reducing atmospheres. For both type of samples, a stepwise thermal decomposition of the gels was noticed in a large temperature range. In the case of samples obtained by microwave-assisted SG method, a higher number of thermal effects were registered assigned to a higher number of molecular species formed in the sample. The residues obtained by non-isothermal treatment up to 900 °C, of both type of samples, were investigated by X-ray diffraction. The results demonstrate the influence of the MW on the SG synthesis and on the thermal properties of the resulted gels. Based on the obtained results, the required thermal treatment of the gels in order to obtain convenient precursors powders for obtaining pure SrCu 2 O 2 could be proposed.

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Section: Resultssupporting

confidence: 89%

Comparative study of the thermal behavior of Sr–Cu–O gels obtained by sol–gel and microwave-assisted sol–gel method

Predoană

Atkinson

Karaj

et al. 2020

J Therm Anal Calorim

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“…The thermal properties of the composite were investigated in air and nitrogen atmospheres by simultaneous thermogravimetry/ differential thermal analysis (TG/DTA). The evolved gases were analyzed by on-line coupled mass spectrometry (TG/ DTA-MS) [24][25][26], which was previously not done in the literature when these precursors were used for the preparation of TiO 2 nanofibers [27].…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of electrospun polyvinylpyrrolidone/titanium tetraisopropoxide composite nanofibers

Kéri

Bárdos

Boyadjiev

et al. 2019

J Therm Anal Calorim

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In this work, polyvinylpyrrolidone/titanium tetraisopropoxide (PVP/TTIP) composite nanofibers were prepared by electrospinning from alcoholic solutions. The morphology and the properties of the fibers were investigated by SEM, Raman spectroscopy, and XRD. The thermal properties and the evolved gases were studied in detail by TG/DTA-MS. The as-spun 800-900-nm-thick PVP/TTIP fibers were then, respectively, annealed in different atmospheres (air and nitrogen) and at different temperatures (550°C, 900°C) in order to obtain anatase and rutile TiO 2 nanofibers. The investigation of the thermal properties was important before the preparation of the oxide nanofibers, because based on them the crystallinity and the composition of the TiO 2 nanofibers could be controlled. Metal oxide nanofibers with a slightly smaller diameter, made up mostly by anatase TiO 2 , were successfully prepared when the annealing was done at 550°C, while at 900°C, rutile TiO 2 fibers were obtained. If nitrogen atmosphere was applied, the nanofibers contained some carbon residue as well.

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“…Less attention was given to study the reactions that take place in the sol-gel solutions during MW irradiation [42][43][44][45].…”

Section: Oxide Nanostructures Obtained By Mw Assisted Sol-gel Methodsmentioning

confidence: 99%

“…Our studies regarding the influence of the microwaves on the reactions in the sol-gel solutions were published by Predoana et al [42] in the case of TiO 2 and V-doped TiO 2 nanostructures.…”

Section: Pure and Doped Oxide Nanostructuresmentioning

confidence: 99%

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Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures

Predoană¹,

Karajz²,

Odhiambo³

et al. 2021

Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects

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Among the chemical methods in the liquid phase, the sol–gel technique is a versatile and efficient method for pure or doped metal oxide films or powders preparation, showing some advantages over other preparation techniques (high homogeneity, the possibility to introducing dopants in large amount, low processing temperature and control over the stoichiometry). Combining the sol–gel (SG)method with the effect of ultrasounds(US) or microwaves (MW) leads to improving the sol–gel procedure. The microwave-assisted sol–gel method is most frequently used for obtaining nanocrystalline, monodispersed oxide nanoparticles, or to transform amorphous gels into well-crystallized nanopowders. Less studied is the influence of the microwaves on the sol–gel reactions in solutions. The benefit of using microwave-assisted sol–gel preparation highly depends on the reagents used and on the composition of the studied systems. In the present chapter, results on the influence of the microwaves on the chemical reactions that take place during the sol–gel synthesis and on the properties of the resulted samples are discussed.

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Thermal behaviour of the TiO2-based gels obtained by microwave-assisted sol–gel method

Cited by 11 publications

References 31 publications

Comparative study of the thermal behavior of Sr–Cu–O gels obtained by sol–gel and microwave-assisted sol–gel method

Comparative study of the thermal behavior of Sr–Cu–O gels obtained by sol–gel and microwave-assisted sol–gel method

Thermal properties of electrospun polyvinylpyrrolidone/titanium tetraisopropoxide composite nanofibers

Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures

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