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Identifier

000415045

Title

Synthesis, characterization and study of photocatalytic activity of organized mesoporous TiO2 frameworks for selective oxidation of benzyl alcohol

Alternative Title

Σύνθεση,χαρακτηρισμός και μελέτη της φωτοκαταλυτικής δραστικότητας οργανωμένων μεσοπορώδων πλεγμάτων TiO2 για εκλεκτική οξείδωση βενζυλικών αλκοολών

Author

Σαββάκης, Μάριος

Thesis advisor

Αρματάς, Γεράσιμος

Reviewer

Βελώνια, Καλλιόπη
Μήλιος, Κωνσταντίνος

Abstract

In this study, well-ordered mesoporous TiO2 frameworks have been successfully prepared by a nano-replication technique, using TiO(NO3)2 compound as the Ti source and mesoporous CMK-3 carbon as the hard template. Powder X-ray-diffraction (XRD), transmission electron microscopy (TEM) and N2 physisorption measurements reveal that the template-free materials possess a three-dimensional (3D) hexagonal mesostructure with large internal BET surface area (up to 256 m2/g) and quite narrow pore-size distribution (~7–8 nm in diameter). Also, the pore walls of these materials exhibit high crystallinity and consist of anatase TiO2 nanocrystals. The combination of a semiconductive framework with large internal surface area and regular mesoporosity makes these materials highly promising for application in photocatalysis. Our results indicated that incorporation of ethylenediamine in the synthesis of TiO2 has a beneficial effect on the visible light response of these mesostructures. Although TiO2 is a wide gap semiconductor that absorbs only UV light ( < 380 nm), our mesoporous TiO2 semiconductors show remarkable UV and visible ( > 420 nm) light activity for the photocatalytic oxidation of various para-substituted benzyl alcohols in presence of molecular oxygen, giving good-to-high yields (ca. 86–100%) of the corresponding aldehydes within a short reaction time (1 – 2 h). The TiO2 mesoporous also exert good long-term cycling stability, raising the possibility for the implementation of this TiO2–O2 photocatalytic system in large-scale production of carbonyl compounds from aromatic alcohols in high yields and with high selectivity.

Language

English

Subject

Mesoporoys materials

Μεσοπορώδη υλικά

Issue date

2018-03-23

Collection

School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses

Type of Work--Post-graduate theses

Permanent Link

https://elocus.lib.uoc.gr//dlib/4/4/1/metadata-dlib-1524133587-840929-4369.tkl