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Photo-induced changes in the Langmuir adsorption constants of metal oxide layers in self-cleaning cation sensors.

Published online by Cambridge University Press:  07 February 2012

Philip S. Foran
Affiliation:
Engineering Department, Lancaster University, Lancaster, LA1 4YW, UK.
Colin Boxall
Affiliation:
Engineering Department, Lancaster University, Lancaster, LA1 4YW, UK.
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Abstract

For the first time, we have used a metal oxide-coated quartz crystal microbalance (QCM) to measure Cs+ adsorption onto illuminated and un-illuminated mesoporous TiO2 (m-TiO2) films by microgravimetric means in-situ. In the simplest case, such experiments yield two parameters of interest: K, the Langmuir adsorption coefficient and m max the maximum mass of adsorbate to form a complete monolayer at the m-TiO2-coated quartz crystal piezoelectric surface. Importantly, we have found that illumination of the m-TiO2 film with ultra bandgap light results in an increase in m max i.e. illumination allows for greater adsorption of substrate to occur than in the dark. Our studies also show that under illumination, K also increases indicating a higher affinity for surface adsorption. The photoinduced change in m max and K are thought to be due to an increase in surface bound titanol groups, thus increasing the number of available adsorption sites – and so providing evidence to support the notion of photoinduced adsorption processes in photocatalytic systems. These findings have implications for the development of a reversible adsorption based microgravimetric sensor for Cs+.

Type
Research Article
Copyright
Copyright © Materials Research Society 2012

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References

REFERENCES

[1] Fujishima, A., Zhang, X. and Tryk, D. A., Surface Science Reports 63(12), 515582 (2008).Google Scholar
[2] Wang, C.-y., Groenzin, H. and Shultz, M. J., Langmuir 19(18), 73307334 (2003).Google Scholar
[3] Pascal-Delannoy, F., Sorli, B. and Boyer, A., Sensors and Actuators a-Physical 84(3), 285291 (2000).Google Scholar
[4] Boxall, C. and Muneer, M., presented at the Third International Conference on Semiconductor Photochemistry, University of Strathclyde, Glasgow, Scotland, 2010 (unpublished).Google Scholar
[5] Yu, J. C., Yu, J. G., Ho, W. K. and Zhao, J. C., Journal of Photochemistry and Photobiology a-Chemistry 148(1-3), 331339 (2002).Google Scholar
[6] Wang, X. D., Shen, J. and Pan, Q., J. Raman Spectrosc. 42(7), 15781582 (2011).Google Scholar
[7] Foran, P. and Boxall, C., Unpublished Work.Google Scholar
[8] Lemon, B. I. and Hupp, J. T., The Journal of Physical Chemistry 100(35), 1457814580 (1996).Google Scholar
[9] Ben-Yoav, H., Amzel, T., Biran, A., Sternheim, M., Belkin, S., Freeman, A. and Shacham-Diamand, Y., Sensors and Actuators B: Chemical 158(1), 366371 (2011).Google Scholar