Johanna Toupin
Water splitting: Study of p-type semiconducting materials as photocathode for protons reduction into H2
Published on 9 February 2016
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Thesis presented on February 09, 2016
Abstract:
The aim of this work was to study p-type semiconducting materials as photocathodes for protons reduction into H2 for water splitting application. Two types of materials have been studied: copper oxides, Cu2O and CuO, and materials with a perovskite structure (ATiO3, A=Ca, Ba, Sr) doped by iron and nitrogen. Copper oxides have been synthetized by two different ways in order to obtain films: sol-gel process coupled with dip-coating and copper plating and anodization. Copper oxides photocorrosion has been highlighted in aqueous environment and under illumination. Their protection via a heterojunction with an n-type semiconductor (TiO2 and BaTiO3) improved electrodes stability over time and photocurrents, thanks to original composition and architecture. Perovskites have been synthetized by sol-gel process coupled with dip-coating. They are well-known as n-type semiconductors; so the study of doping with iron, to substitute titanium, and with nitrogen, to substitute oxygen, shows a change from n-type to p-type, and a reduction of the band gap. The physical and chemical properties of the synthetized electrodes were characterized (crystal structure, morphology, optical and photoelectrochemical properties) and discussed according to the composition and synthesis parameters. This work enables to obtain original, efficient, and stable over time, photocathodes (protected copper oxides) and to demonstrate the potential use of doped perovskites for this application.
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