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Catalytic and photocatalytic processes on 18O-labeled TiO2
Kavan, Ladislav ; Zukalová, Markéta ; Ferus, Martin ; Kürti, J. ; Koltai, J. ; Civiš, Svatopluk
18O-isotope labelled titania (anatase, rutile) was synthesized. The products were characterized by Raman spectra together with their quantum chemical modelling. The interaction with carbon dioxide was investigated using high-resolution FTIR spectroscopy, in dark and upon UV-excitation. The oxygen isotope exchange at the Ti18O2/C16O2 interface was elucidated. The C18O2 was formed as the dominating final product with a minor content of C16O18O. The rate of oxygen-isotope exchange is highly sensitive to the conditions of the titania pretreatment. The vacuum-annealed Ti18O2 at 450 C exhibited a very high spontaneous oxygen exchange activity with gaseous C16O2. A mechanism for the 18O/16O exchange process is discussed at the molecular level. The photocatalytic formation of methane, acetylene and C16O released from the Ti18O2 surface was triggered by an XeCl excimer laser irradiation.
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