In a typical water splitting photoelectrochemical (PEC) cell, once the light is being absorbed by the semiconductor electrode and generated charges upon excitation, the majority carriers (electrons in a n-type semiconductor) travel to the substrate and collected at the substrate before transferred to the counter electrode where the hydrogen evolution takes place. The remaining holes need to travel to the semiconductor/electrolyte interface to under go water oxidation [1].

Maximising the light absorption while overcoming the electron-hole recombination is a key challenges in the PEC water splitting. A range of transition metal oxide semiconductor electrodes is being currently investigated with the aim of meeting those challenges in our group [2]. We have recently prepared nanostructured alpha-Fe₂O₃ electrodes by aerosol assisted chemical vapour deposition of a hexanuclear Iron(III) complex [2]. These electrodes have shown 0.3 mAcm-2 without any dopants. Photoelectrochemical properties of those electrodes show that they are suitable for the PEC water splitting process. This presentation describes the synthesis of hexanuclear complex, preparation of thin film Fe₂O₃ electrodes and photoelectrochemical characterisation. Our recent work on other nanostructured metal oxide semiconductors such as NiTiO₃ will also be included in the presentation.


References:
(1). K.G.U.Wijayantha and D.H. Auty, Twin Cell Technology for Hydrogen Generation. (In: Encyclopaedia of Materials: Science and Technology Updates, Elsevier, Oxford, pages 1-5, 2005.
(2). Asif A. Tahir, K.G.U. Wijayantha, Vickie McKee, Muhammd Mazhar, and Sina Saremi, Nanostructured Haematite thin films derived from hexanuclear Fe(III) complexes for PEC water splitting, in preparation.