2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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TechConnect Summit
Clean Technology 2008

Photo-electrochemical Generation of Hydrogen using Plasma Assisted Self-assembled Titania Nanotubes

M.K. Mazumder, R. Sharma, P. Das, A.S. Biris, M. Misra
University of Arkansas at Little Rock, US

Keywords:
plasma treatment, titania nanotubes, photoconversion, hydrogen

Abstract:
Of many semiconducting materials available for converting solar radiation energy to hydrogen by splitting water, TiO2 is attractive since its use was first reported in 1972, offering its low cost, chemically resistant, and inert properties. Yet its wide band gap (3.0 to 3.2 eV) can only harvest five percent of the total solar energy spectrum. While n-type doping of titania can reduce the band gap within the bulk of the semiconductor, the surface defects cause Fermi level pinning by creating an energy barrier against the transport of photo-generated electrons at the photo-anode-electrolyte interface when exposed to light. We report here the application of nano-structured titania photo-anodes with nitrogen plasma surface treatment for improving the surface properties and minimizing the surface states. The photocurrent density increased form 0. 8 mA/cm2 without the plasma surface treatment to 1.6 mA/cm2 with the surface modification. The experiments were performed under identical conditions with the photo-anodes illuminated by solar radiation produced by a xenon lamp solar radiation simulator. The result shows that the surface treatments improve the performance of the titania nanostructured photoanodes by removing surface contaminants, charge carrier traps, and improving wetting properties and charge transfer rates, and the surface structure leading to 100 percent increase in photo-current density.


Nanotech 2008 Conference Program Abstract