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Εντολή Αναζήτησης : Συγγραφέας="Λυκάκης" Και Συγγραφέας="Ιωάννης"

Τρέχουσα Εγγραφή: 8 από 13

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Κωδικός Πόρου

000398769

Τίτλος

Ανάπτυξη σύνθετων νανοδομημένων πλεγμάτων Cu/CeO2 για τη φωτοκαταλυτική διάσπαση του νερού προς παραγωγή οξυγόνου

Συγγραφέας

Μαρκουλάκη, Βασιλική

Σύμβουλος διατριβής

Αρματάς, Γεράσιμος

Μέλος κριτικής επιτροπής

Λυκάκης, Ιωάννης
Μήλιος, Κωνσταντίνος

Περίληψη

Porous cerium-rich metal oxide materials have recently emerged as promising candidates for photocatalytic oxygen evolution reaction (OER). The high catalytic activity of such materials could be attributed to the nanoscale structure, large internal surface area and, most importantly, the ability to adsorb and desorb molecular oxygen into the crystal lattice. As a result, oxygen cavities can be formed which play a significant role in catalytic processes. In this thesis work we report the synthesis of ordered mesoporous CeO2 and Cu/CeO2 composite frameworks with different content of CuO and demonstrate their activity for photocatalytic O2 production via UV–vis light-driven oxidation of water. Mesoporous Cu/CeO2 have been successfully prepared by a nanocasting route, using mesoporous silica (SBA-15) as a rigid template. Two different synthetic pathways were used to obtain porous Cu/CeO2 composites: the first one involved the presence of moisture in the silica template, and in the second pathway, the silica template was dried at elevated temperature (150o C). X-ray diffraction (XRD), electron transition microscopy (TEM) and N2 porosimetry analyses revealed that as-prepared samples have a mesoporous structure composed of parallel arranged nanorods, with high surface area and narrow pore size distribution. Interestingly, we found that in the absence of moisture (within the silica pores), the present method gives porous Cu/CeO2 composites with improved textural characteristics (surface area and pore volume). The molecular structure and optical properties of composite frameworks were investigated with Raman and UV–vis/NIR diffuse reflectance spectroscopy. Catalytic results indicated that incorporation of CuO clusters in the CeO2 lattice improved the photochemical properties. As a result, the Cu/CeO2 mesoporous catalyst containing ~38 wt% of CuO loading reach a high O2 evolution rate of ~19.6 μmol h-1 (or 392 μmol h-1 g-1) with an apparent quantum efficiency of 17.6% at  = 365 ± 10 nm, which compares favorable with that obtained from non-porous Cu/CeO2 counterpart and pure mesoporous CeO2.

Φυσική περιγραφή

65 σ. : πίν.,σχήμ. ; 30 εκ.

Γλώσσα

Ελληνικά

Θέμα

Mixed metal oxides

Nanocasting

Water photo-oxidation

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