Your browser does not support JavaScript!

Home    Μεσοπορώδεις ετεροδομές Ag2S/CdS και πολυοξομεταλλικών πλειάδων για φωτοκαταλυτική οξείδωση βενζυλο-αλκοολών  

Results - Details

Add to Basket
[Add to Basket]
Identifier 000383739
Title Μεσοπορώδεις ετεροδομές Ag2S/CdS και πολυοξομεταλλικών πλειάδων για φωτοκαταλυτική οξείδωση βενζυλο-αλκοολών
Alternative Title Mesoporous eterostructures Ag2S/CdS and polyoxometallete compaunds for photocatalytic oxidation of benzyl-alcohols
Author Κορναράκης, Ιωάννης
Thesis advisor Αρματάς, Γεράσιμος
Reviewer Κιογέογλου, Γεώργιος
Τρικαλίτης, Παντελής
Abstract Porous multicomponent semiconductor materials promise improved photocatalytic performance due to the large and accessible pore surface area and high charge separation efficiency. Here we report the synthesis of well-ordered porous polyoxometalate (POM)/Ag2S/CdS hybrid mesostructures featuring controllable composition and high photocatalytic activity via a two-step hard-templating and topotactic ion-exchange chemical process. Ag2S compound and polyoxometalate cluster anions with different reduction potential, such as PW12O403-, SiW12O404- and PMo12O403-, were employed as electron acceptors in these ternary heterojunction photocatalysts. Characterization by small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 physisorption measurements showed hexagonal arrays of POM–Ag2S–CdS hybrid nanorods with large internal BET surface area and uniform pores. Moreover, the Keggin structure of the incorporated POM clusters was verified by elemental X-ray spectroscopy microanalysis (EDS), infrared (IR) and diffuse-reflectance ultraviolet-visible (UV/vis) spectroscopy. These new porous heterostructures were implemented as visible-light-driven photocatalysts, displaying exceptional high activity in aerobic oxidation of various para-substituted benzyl alcohols to the corresponding ketones. Our catalytic experiments together with photoluminescence (PL) measurements show that the spatial separation of photogenerated electrons and holes at CdS through the potential gradient along the CdS–Ag2S–POM interfaces is responsible for the increased photocatalytic activity.
Language Greek
Subject Mesoporous
Photocatalysis Chalcogenides
Μεσοπορώδες
Φωτοκατάλυση
Χαλκογονίδια
Issue date 2014-03-28
Collection   School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses
  Type of Work--Post-graduate theses
Views 214

Digital Documents
No preview available

Download document
View document
Views : 18