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Proceedings Paper

Effect of niobium segregation on surface properties of titanium dioxide
Author(s): L. R. Sheppard; A. Atanacio; T. Bak; J. Nowotny; K. E. Prince
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Paper Abstract

The present paper considers the effect of segregation on the performance of photo-electrode materials for photo-electrochemical water splitting. This phenomenon, which alters the surface composition of a material during processing at elevated temperatures, has the capacity to dominate interfacial charge transfer between the photo-electrode and the electrolyte. As the present understanding of segregation in metal oxides is limited, this paper aims at addressing the need to collect empirical data which can be used for the development of novel materials. In the present investigation, Nb surface segregation was investigated at 1273 K under high and low oxygen activity using secondary ion mass spectrometry (SIMS). A calibration procedure was used to enable quantifiable data and Nb was observed to segregate strongly, especially at high oxygen activity. While this was attributed to the defect disorder, it remained unclear whether gas/solid equilibrium was achieved, and consequently whether the observed behaviour represents equilibrium segregation. Irrespectively, the observed behaviour clearly illustrates how the surface composition of a metal oxide can be altered through the control of segregation. This must be considered in the pursuit of high performance photo-electrode materials for water splitting under sunlight.

Paper Details

Date Published: 8 September 2006
PDF: 9 pages
Proc. SPIE 6340, Solar Hydrogen and Nanotechnology, 634015 (8 September 2006); doi: 10.1117/12.674547
Show Author Affiliations
L. R. Sheppard, Univ. of New South Wales (Australia)
A. Atanacio, Australian Nuclear Science and Technology Organisation (Australia)
T. Bak, Univ. of New South Wales (Australia)
J. Nowotny, Univ. of New South Wales (Australia)
K. E. Prince, Australian Nuclear Science and Technology Organisation (Australia)

Published in SPIE Proceedings Vol. 6340:
Solar Hydrogen and Nanotechnology
Lionel Vayssieres, Editor(s)

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