Why is anatase a better photocatalyst than rutile? - Model studies on epitaxial TiO2 films
By T. Luttrell, Sandamali Halpegamage, J. Tao, A. Kramer, E. Sutter, M. Batzill. Scientific Reports, 2014
1,389 citations recorded by the source corpus.
The prototypical photocatalyst TiO2 exists in different polymorphs, the most common forms are the anatase- and rutile-crystal structures. Generally, anatase is more active than rutile, but no consensus exists to explain this difference. Here we demonstrate that it is the bulk transport of excitons to the surface that contributes to the difference. Utilizing high –quality epitaxial TiO2 films of the two polymorphs we evaluate the photocatalytic activity as a function of TiO2-film thickness. For anatase the activity increases for films up to ~5 nm thick, while rutile films reach their maximum activity for ~2.5 nm films already. This shows that charge carriers excited deeper in the bulk contribute to surface reactions in anatase than in rutile. Furthermore, we measure surface orientation dependent activity on rutile single crystals. The pronounced orientation-dependent activity can also be correlated to anisotropic bulk charge carrier mobility, suggesting general importance of bulk charge diffusion for explaining photocatalytic anisotropies.
Subfields: Materials Chemistry, Renewable Energy, Sustainability and the Environment
View Paper: https://www.semanticscholar.org/paper/89fd206646c5f86803732db3a92d99836b4e9aba
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In Materials Chemistry
Citations in the corpus
- New strategy for microplastic degradation: Green photocatalysis using a protein-based porous N-TiO2 semiconductor (2019, background): “Synthesis and characterization of N-TiO2 semiconductors As shown in Figure 1, both N-TiO2 materials were synthesized in the anatase crystalline phase, which is known to be responsible for the photocatalytic activity of the material [29].”
- Sol gel graphene/TiO2 nanoparticles for the photocatalytic-assisted sensing and abatement of NO2 (2019, background): “2 eV;∼388 nm) reported in the literature [47], thus the direct allowed model would seem more applicable for these specimens.”