Σύνθεση νανοσύνθετων φωτοκαταλυτών TiO2 / g-C3N4 με ηλεκτροστατική ινοποίηση, χαρακτηρισμός και φωτοκαταλυτική δραστικότητα (Master thesis)

Μπαϊράμης, Φειδίας


In the present thesis, TiO2/g-C3N4 nanofibers have been synthesized via electrospinning technique (25 kV) and the characterization of the photocatalysts was performed in liquid phase and under solar light irradiation. G-C3N4 has been synthesized firstly by thermal condensation process using urea as precursor compound. Then, composite TiO2/g-C3N4 nanofibers have been synthesized with the following ratios of x% g-C3N4/TiO2, x= 1%, 2.5%, 5% (weight by weight, wt%) nanofibers using tetraisopropoxide as the precursor of TiO2 and polyvinylpyrrolidone (PVP) polymer (Μw: 1.300.000) in absolute ethanol solvent and acetic acid for the hydrolysis of Ti(Pro)4. The materials were calcined at 550 oC and named as GNT1%, GNT2.5% and GNT5%, respectively. TiO2 fibers were also prepared with same procedures and used as reference material.The characterization of the photocatalysts was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), N2 porosimetry, dynamic light scattering (DLS), fluorescence spectroscopy for the quantification of •OH radicals by the hydroxyl – terephthalic acid method and Fourier transformed infrared spectroscopy (FT-IR). Based on the results obtained from the previous characterization techniques the produced titania is two-phase and consists mainly of anatase (80.0-85.1%) and in low contents rutile (14.9-20.0%), the diameter of nanofibers varied between 200-300 nm for all samples, the band gap of the photocatalysts was lower than 3.0 eV confirming the shift of the absorption edge of the samples to visible-light region. Furthemore, the photocatalysts are mesoporous materials type VI (a) according to IUPAC classification with specific Brunauer-Emmett-Teller (BET) surface areas among 40.0-47.6 m2/g. Moreover, from the fluorescence measurements, the formation of •OH radicals increases as the doping percent of g-C3N4 in TiO2 nanofibers also increases, following the trend ΤiΟ2 < GNT1% < GNT2.5% < GNT5%. The photocatalytic activity of the fiber materials was studied against the degradation of methylene blue dye under simulated sunlight irradiation (Suntest, λ>300 nm, I=500 Wm-2) confirming a high photocatalytic performance and their potential for green chemistry and technology applications.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
Subject classification: Ρύπανση των υδάτων
Φωτοκατάλυση
Keywords: Φωτοκαταλυτική δραστηριότητα,Ηλεκτροστατική ινοποίηση,Ετεροδομές ΤiO2/g-C3N4,Photocatalytic activity,Electrospinning technique
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/29132
Appears in Collections:Διατριβές Μεταπτυχιακής Έρευνας (Masters)

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