Author/Authors :
Sun، نويسنده , , Xiaoming and Dyballa، نويسنده , , Michael and Yan، نويسنده , , Junqing and Li، نويسنده , , Landong and Guan، نويسنده , , Naijia and Hunger، نويسنده , , Michael، نويسنده ,
Abstract :
Quantitative 17O MAS NMR investigation of the 16/17O isotope exchange on pure-anatase TiO2/A and mixed-phase TiO2/A + R with an anatase to rutile ratio of 1:1 has been performed. Evaluation of the exchange kinetics hints to a strong decrease of the activation energy of this reaction on mixed-phase TiO2/A + R material (61 (A) and 70 kJ/mol (R)) compared with pure-anatase TiO2/A (105 kJ/mol). Furthermore, a very rapid increase of the 17O MAS NMR signals of surface oxygen species indicates a preferred 16/17O isotope exchange at these sites and a subsequently exchange with 16O framework atoms in the anatase and rutile domains.
