Influence of the Ti content on the photocatalytic oxidation of 2-propanol and CO on TiSiBEA zeolites

TixSiBEA (x = 1.5, 3.2 and 5.8 Ti wt.%) zeolites were prepared by a two-step postsynthesis method reported earlier (Chem. Commun. 1998, 87). Diffuse reflectance (DR) UV–vis and photoluminescence data suggest that mainly isolated tetrahedral framework Ti ions are present in Ti1.5SiBEA and Ti3.2SiBEA zeolites. These ions which in their excited triplet state easily interact with CO molecules as shown by photoluminescence data, are believed to be the active sites of the photocatalytic liquid phase oxidation of 2-propanol by dissolved oxygen and of photocatalytic gas phase oxidation of CO by N2O as suggested by catalytic measurements.

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► Isolated tetrahedral framework Ti species mainly present in TiSiBEA zeolites.
► These Ti species in their excited triplet state are active sites of the photocatalytic oxidation of 2-propanol and CO.
► Photocatalytic activity of TiSiBEA depends on Ti content and is related to the amount of tetrahedral and octahedral Ti(IV).