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Proceedings Paper

Photocatalytic evolution of molecular hydrogen and oxygen over La-doped NaTaO3 particles: Effect of different cocatalysts (Presentation Recording)
Author(s): Irina Ivanova; Tarek Kandiel; Amer Hakki; Ralf Dillert; Detlef W. Bahnemann

Paper Abstract

To solve the global energy and environmental issues highly efficient systems for solar energy conversion and storage are needed. One of them involves the photocatalytic conversion of solar energy into the storable fuel molecular hydrogen via the water splitting process utilizing metal-oxide semiconductors as catalysts. Since photocatalytic water splitting is still a rather poorly understood reaction, fundamental research in this field is required. Herein, the photocatalytic activity for water splitting was investigated utilizing La-doped NaTaO3 as a model photocatalyst. The activity of La-doped NaTaO3 was assessed by the determination of the overall quantum yield of molecular hydrogen and molecular oxygen evolution. In pure water La-doped NaTaO3 exhibits rather poor activity for the photocatalytic H2 evolution whereby no O2 was detected. To enhance the photocatalytic activity the surface of La-doped NaTaO3 was modified with various cocatalysts including noble metals (Pt, Au and Rh) and metal oxides (NiO, CuO, CoO, AgO and RuO2). The photocatalytic activity was evaluated in pure water, in aqueous methanol solution, and in aqueous silver nitrate solution. The results reveal that cocatalysts such as RuO2 or CuO exhibiting the highest catalytic activity for H2 evolution from pure water, possess, however, the lowest activity for O2 evolution from aqueous silver nitrate solution. La-doped NaTaO3 modified with Pt shows the highest quantum yield of 33 % with respect to the H2 evolution in the presence of methanol. To clarify the role of methanol in such a photocatalytic system, long-term investigations and isotopic studies were performed. The underlying mechanisms of methanol oxidation were elucidated.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9560, Solar Hydrogen and Nanotechnology X, 95600V (5 October 2015); doi: 10.1117/12.2186561
Show Author Affiliations
Irina Ivanova, Leibniz Univ. Hannover (Germany)
Tarek Kandiel, Sohag Univ. (Egypt)
Amer Hakki, Leibniz Univ. Hannover (Germany)
Ralf Dillert, Leibniz Univ. Hannover (Germany)
Detlef W. Bahnemann, Leibniz Univ. Hannover (Germany)


Published in SPIE Proceedings Vol. 9560:
Solar Hydrogen and Nanotechnology X
Shaohua Shen, Editor(s)

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