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|Title:||Polymorphism of nanocrystalline TiO2 prepared in a stagnation flame: Formation of the TiO2-II phase||Authors:||Manuputty, M.Y.
|Issue Date:||2019||Publisher:||Royal Society of Chemistry||Citation:||Manuputty, M.Y., Dreyer, J.A.H., Sheng, Y., Bringley, E.J., Botero, M.L., Akroyd, J., Kraft, M. (2019). Polymorphism of nanocrystalline TiO2 prepared in a stagnation flame: Formation of the TiO2-II phase. Chemical Science 10 (5) : 1342-1350. ScholarBank@NUS Repository. https://doi.org/10.1039/c8sc02969e||Rights:||Attribution-NonCommercial 4.0 International||Abstract:||A metastable "high-pressure" phase known as ?-PbO2-type TiO2 or TiO2-II is prepared via a single-step synthesis using a laminar premixed stagnation flame. Three other TiO2 polymorphs, namely anatase, rutile and TiO2-B phases, can also be obtained by tuning the oxygen/fuel ratio. TiO2-II is observed as a mixture with rutile under oxygen-lean flame conditions. To the best of our knowledge, this is the first time that this phase has been identified in flame-synthesised TiO2. The formation of TiO2-II in an atmospheric pressure flame cannot be explained thermodynamically and is hypothesised to be kinetically driven through the oxidation and solid-state transformation of a sub-oxide TiO2-x intermediate. In this scenario, rutile is nucleated from the metastable TiO2-II phase instead of directly from a molten/amorphous state. Mixtures containing three-phase heterojunctions of anatase, rutile, and TiO2-II nanoparticles as prepared here in slightly oxygen-lean flames might be important in photocatalysis due to enhanced electron-hole separation. © The Royal Society of Chemistry 2019.||Source Title:||Chemical Science||URI:||https://scholarbank.nus.edu.sg/handle/10635/213750||ISSN:||20416520||DOI:||10.1039/c8sc02969e||Rights:||Attribution-NonCommercial 4.0 International|
|Appears in Collections:||Staff Publications|
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