Letter | Published:

Anatase TiO2 single crystals with a large percentage of reactive facets

Nature volume 453, pages 638641 (29 May 2008) | Download Citation

Abstract

Owing to their scientific and technological importance, inorganic single crystals with highly reactive surfaces have long been studied1,2,3,4,5,6,7,8,9,10,11,12,13. Unfortunately, surfaces with high reactivity usually diminish rapidly during the crystal growth process as a result of the minimization of surface energy. A typical example is titanium dioxide (TiO2), which has promising energy and environmental applications14,15,16,17. Most available anatase TiO2 crystals are dominated by the thermodynamically stable {101} facets (more than 94 per cent, according to the Wulff construction10), rather than the much more reactive {001} facets8,9,10,11,12,13,18,19,20. Here we demonstrate that for fluorine-terminated surfaces this relative stability is reversed: {001} is energetically preferable to {101}. We explored this effect systematically for a range of non-metallic adsorbate atoms by first-principle quantum chemical calculations. On the basis of theoretical predictions, we have synthesized uniform anatase TiO2 single crystals with a high percentage (47 per cent) of {001} facets using hydrofluoric acid as a morphology controlling agent. Moreover, the fluorated surface of anatase single crystals can easily be cleaned using heat treatment to render a fluorine-free surface without altering the crystal structure and morphology.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    , , , & Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electro-oxidation activity. Science 316, 732–735 (2007)

  2. 2.

    et al. Direct visualization of defect-mediated dissociation of water on TiO2 (110). Nature Mater. 5, 189–192 (2006)

  3. 3.

    et al. Electron-induced oxygen desorption from the TiO2 (011)-2 × 1 surface leads to self-organized vacancies. Science 317, 1052–1056 (2007)

  4. 4.

    , , & Steps on anatase TiO2 (101). Nature Mater. 5, 665–670 (2006)

  5. 5.

    The surface science of titanium dioxide. Surf. Sci. Rep. 48, 53–229 (2003)

  6. 6.

    et al. Resonant photoemission of anatase TiO2 (101) and (001) single crystals. Phys. Rev. B 67, 035110 (2003)

  7. 7.

    , , , & Electrochemical and photoelectrochemical investigation of single-crystal anatase. J. Am. Chem. Soc. 118, 6716–6723 (1996)

  8. 8.

    & Reactivity of anatase TiO2 nanoparticles: the role of the minority (001) surface. J. Phys. Chem. B 109, 19560–19562 (2005)

  9. 9.

    , & Structure determination of the two-domain (1 × 4) anatase TiO2(001) surface. Phys. Rev. Lett. 84, 3354–3357 (2000)

  10. 10.

    , & Structure and energetics of stoichiometric TiO2 anatase surfaces. Phys. Rev. B 63, 155409 (2001)

  11. 11.

    , , & Structure and energetics of water adsorbed at TiO2 anatase (101) and (001) surfaces. Phys. Rev. Lett. 81, 2954–2957 (1998)

  12. 12.

    , & Chemistry of and on TiO2-anatase surfaces by DFT calculations: a partial review. Theor. Chem. Acc. 117, 663–671 (2007)

  13. 13.

    & Stress-driven reconstruction of an oxide surface: the anatase TiO2(001)-(1 × 4) surface. Phys. Rev. Lett. 87, 266105 (2001)

  14. 14.

    & Electrochemical photolysis of water at a semiconductor electrode. Nature 238, 37–38 (1972)

  15. 15.

    & A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films. Nature 353, 737–740 (1991)

  16. 16.

    Photoelectrochemical cells. Nature 414, 338–344 (2001)

  17. 17.

    et al. Nanocrystalline titanium oxide electrodes for photovoltaic applications. J. Am. Ceram. Soc. 80, 3157–3171 (1997)

  18. 18.

    & Morphology development and crystal growth in nanocrystalline aggregates under hydrothermal conditions: Insights from titania. Geochim. Cosmochim. Acta 63, 1549–1557 (1999)

  19. 19.

    , , , & The effect of the preparation condition of TiO2 colloids on their surface structures. J. Phys. Chem. B 104, 4130–4133 (2000)

  20. 20.

    et al. Surfactant-assisted elimination of a high energy facet as a means of controlling the shapes of TiO2 nanocrystals. J. Am. Chem. Soc. 125, 15981–15985 (2003)

  21. 21.

    & Prediction of TiO2 nanoparticle phase and shape transitions controlled by surface chemistry. Nano Lett. 5, 1261–1266 (2005)

  22. 22.

    & Titanium dioxide nanomaterials: synthesis, properties, modifications, and applications. Chem. Rev. 107, 2891–2959 (2007)

  23. 23.

    The polymorphic crystallization of titanium (IV) oxide under hydrothermal conditions. II. The roles of inorganic anions in the nucleation of rutile and anatase from acid solutions. Bull. Chem. Soc. Jpn 51, 1771–1776 (1978)

  24. 24.

    , & Growth and Raman spectroscopic characterization of TiO2 anatase single crystals. J. Cryst. Growth 130, 108–112 (1993)

  25. 25.

    & Mass spectrometric studies at high temperatures. XVI. Sublimation pressures for TiF3 (g) and the stabilities of TiF2 (g) and TiF (g). J. Phys. Chem. 71, 2893–2895 (1967)

  26. 26.

    & in Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules 642 (Van Nostrand Reinhold, New York, 1979)

  27. 27.

    & A model for the phase stability of arbitrary nanoparticles as a function of size and shape. J. Chem. Phys. 121, 4276–4283 (2004)

  28. 28.

    & Preparation of hollow anatase TiO2 nanospheres via Ostwald ripening. J. Phys. Chem. B 108, 3492–3495 (2004)

  29. 29.

    , , , & Effects of F- doping on the photocatalytic activity and microstructures of nanocrystalline TiO2 powders. Chem. Mater. 14, 3808–3816 (2002)

  30. 30.

    & Complex α-MoO3 nanostructures with external bonding capacity for self-assembly. J. Am. Chem. Soc. 125, 2697–2704 (2003)

  31. 31.

    & Self-consistent equations including exchange and correlation effects. Phys. Rev. B 140, A1133–A1138 (1965)

  32. 32.

    , & Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996)

  33. 33.

    & From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999)

  34. 34.

    & Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996)

  35. 35.

    & Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996)

  36. 36.

    & Creation of intestine-like interior space for metal-oxide nanostructures with a quasi-reverse emulsion. Angew. Chem. Int. Ed. 43, 5206–5209 (2004)

  37. 37.

    & Synthetic architectures of TiO2/H2Ti5O11·H2O, ZnO/H2Ti5O11·H2O, ZnO/TiO2/H2Ti5O11·H2O and ZnO/TiO2 nanocomposites. J. Am. Chem. Soc. 127, 270–278 (2005)

Download references

Acknowledgements

This work was supported by the Australian Research Council. H.G.Y. wishes to express his gratitude to the National University of Singapore, where the preliminary experimental work was carried out. The authors acknowledge Qiu Hong Hu for her help with statistical analysis.

Author information

Author notes

    • Hua Gui Yang
    •  & Cheng Hua Sun

    These authors contributed equally to this work.

Affiliations

  1. ARC Centre of Excellence for Functional Nanomaterials, School of Engineering and Australian Institute for Bioengineering and Nanotechnology,

    • Hua Gui Yang
    • , Cheng Hua Sun
    • , Shi Zhang Qiao
    • , Gang Liu
    • , Sean Campbell Smith
    •  & Gao Qing Lu
  2. Centre for Computational Molecular Science, Australian Institute for Bioengineering and Nanotechnology,

    • Cheng Hua Sun
    •  & Sean Campbell Smith
  3. Centre for Microscopy and Microanalysis and School of Engineering, The University of Queensland, Queensland 4072, Australia

    • Jin Zou
  4. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China

    • Gang Liu
    •  & Hui Ming Cheng

Authors

  1. Search for Hua Gui Yang in:

  2. Search for Cheng Hua Sun in:

  3. Search for Shi Zhang Qiao in:

  4. Search for Jin Zou in:

  5. Search for Gang Liu in:

  6. Search for Sean Campbell Smith in:

  7. Search for Hui Ming Cheng in:

  8. Search for Gao Qing Lu in:

Corresponding authors

Correspondence to Shi Zhang Qiao or Gao Qing Lu.

Supplementary information

PDF files

  1. 1.

    Supplementray Information

    The file contains Supplementary Notes and Supplementary Figures S1-S8 with legends. The Supplementary Information is divided into two parts: Calculation Section and Experiment Section. Calculation Section contains structural models, computational methods, reliability of methods, extensive test based on (4x4) slab models, stabilization mechanism of fluorine atoms, and additional references. Experiment Section has 5 additional figures (Figure S4-S8 with legends).

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature06964

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.