Shape-enhanced Photocatalytic Activity of Single-crystalline Anatase TiO2 (101) Nanobelts
By N. Wu, Jin Wang, D. Tafen, Hong Wang, Jian-guo Zheng, James P. Lewis, Xiaogang Liu, S. Leonard, A. Manivannan. Journal of the American Chemical Society, 2010
697 citations recorded by the source corpus.
Particle size is generally considered to be the primary factor in design of nanocrystal photocatalyst, because the reduction of particle size increases the number of active sites. However, the benefit from the size reduction can be canceled by a higher electron-hole recombination rate due to the confined space in sphere-shaped nanoparticles. Here we report a mechanistic study on a novel nanobelt structure that overcomes the drawback of sphere-shaped nanoparticles. Single-crystalline anatase TiO2 nanobelts with two dominant surfaces of (101) facet exhibit enhanced photocatalytic activity than the nanosphere counterparts with an identical crystal phase and similar specific surface area. The ab initio density functional theory (DFT) calculations show that the exposed (101) facet of the nanobelts yields an enhanced reactivity with molecular O2, facilitating the generation of superoxide radical. Moreover, the nanobelts exhibit a lower electron-hole recombination rate than the nanospheres due to the following three reasons: (i) greater charge mobility in the nanobelts, which is enabled along the longitudinal dimension of the crystals; (ii) fewer localized states near the band edges and in the bandgap due to less unpassivated surface states in the nanobelts; and (iii) enhanced charge separation due to trapping of photogenerated electrons by chemisorbed molecular O2 on the (101) facet. Our results suggest that the photocatalysis efficiency of nanocrystals can be significantly improved by tailoring the shape and the surface structure of nanocrystals, which provides a new concept for rational design and development of high-performance photocatalysts.
Subfields: Materials Chemistry, Renewable Energy, Sustainability and the Environment
View Paper: https://www.semanticscholar.org/paper/4ea7645a62f1383091a251b2e99659b86b8beec4
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Citations in the corpus
- Ti 3+ in the surface of titanium dioxide: generation, properties and photocatalytic application (2012, background): “These studies have been motivated in part by the discovery that TiO2 is a photocatalyst with relatively high efficiency for the decomposition of water [2–8] and the degradation of organic species [9–19].”