Instability of Hydrogenated TiO2

Manjula I. Nandasiri, Vaithiyalingam Shutthanandan, Sandeep Manandhar, Ashleigh M. Schwarz, Lucas Oxenford, John V. Kennedy, Suntharampillai Thevuthasan, Michael A. Henderson

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Abstract

Hydrogenated TiO2 (H-TiO2) is touted as a viable visible light photocatalyst. We report a systematic study on the thermal stability of H-implanted TiO2 using nuclear reaction analysis (NRA), Rutherford backscattering spectrometry, ultraviolet photoelectron spectroscopy, and X-ray photoelectron spectroscopy. Protons (40 keV) implanted at a ∼2 atom % level within a ∼120 nm wide profile of rutile TiO2(110) were situated ∼300 nm below the surface. NRA revealed that this H-profile broadened toward the surface after annealing at 373 K, dissipated out of the crystal into vacuum at 473 K, and was absent within the beam sampling depth (∼800 nm) at 523 K. Photoemission showed that the surface was reduced in concert with these changes. Similar anneals had no effect on pristine TiO2(110). The facile bulk diffusivity of H in rutile at low temperatures, as well as its interfacial activity toward reduction, significantly limits the utilization of H-TiO2 as a photocatalyst.

Original languageEnglish
Pages (from-to)4627-4632
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume6
Issue number22
DOIs
Publication statusPublished - 19 Nov 2015
Externally publishedYes

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Keywords

  • diffusion
  • hydrogen
  • implantation
  • rutile
  • surface reduction
  • TiO(110)

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Nandasiri, M. I., Shutthanandan, V., Manandhar, S., Schwarz, A. M., Oxenford, L., Kennedy, J. V., Thevuthasan, S., & Henderson, M. A. (2015). Instability of Hydrogenated TiO2 Journal of Physical Chemistry Letters, 6(22), 4627-4632. https://doi.org/10.1021/acs.jpclett.5b02219