283618 Titanium Supported Iron Oxide for Photo-Electrochemical Hydrogen Production

Wednesday, October 31, 2012: 10:30 AM
316 (Convention Center )
C.-K. Ong1, Stephen Dennison1, Geoffrey Kelsall1 and Klaus Hellgardt2, (1)Imperial College London, London, United Kingdom, (2)Chemical Engineering, Imperial College London, London, United Kingdom

The total global energy consumption today is about 14 TW and is expected to double by the year 2050. There is a heavy dependency on fossil fuels to meet this energy demand, which contributes significantly to global CO2 emissions. Hydrogen is a clean energy carrier, which could supply future energy demand whilst minimising CO2 emissions, provided that the hydrogen is produced in a clean and sustainable process such as by photo-electrolysis.

Photo-electrolysis offers a potentially elegant solution to the capture of solar energy by directly facilitating the splitting of water to produce hydrogen and oxygen. The feasibility of this process is well established and much work is devoted to finding and developing improved photo anodes for oxygen evolution.

The current state of the art for photo-electrolysis systems is restricted to small, lab-scale, photo-electrochemical cells which cannot produce useful quantities of hydrogen. In order to scale up photo-electrochemical systems the photo-electrodes need to be deposited onto larger electrode areas. Conventional support electrodes are ITO (indium doped tin oxide) or FTO (fluorine doped tin oxide) substrates. Our previous work has shown that the use of fluorine-dope tin oxide (FTO) substrates would result in a large lateral potential drop, rendering most of the exposed photo electrode surface area inactive for the photo oxidation/reduction of water. This can be avoided if a more conductive substrate such as stainless steel or titanium is employed.

In this paper we will present and compare our results of the photo-activity of Fe2O3 deposited by spray pyrolysis onto both, FTO and titanium substrates (Figure 1). We will show that the control of the metal oxide interface layer is crucial in achieving high photocurrents in the case of titanium substrates.

Figure 1:    Cyclic voltamogram of Fe2O3 deposited onto TEC-8 FTO and titanium substrate under

42 Wm-2 white light illumination

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