Photocatalytic water splitting can play an important role for the generation of hydrogen. It has been recently found that gold nanoparticles acting as dyes enhance the photocatalytic activity of TiO2 in the visible region1. Also recently we have show that cerium nanoparticles of a small size can be a semiconductor for the photocatalytic oxygen generation from water and also in this case deposition of gold increases the photoresponse to the visible region2. In this previous report hydrogen and oxygen generation has been performed in the presence of sacrificial agent. Now we have combined the activity of both semiconductors in a Z-scheme device for the visible light overall water splitting. Scheme 1 illustrates the photocatalytic system and indicates the initial reaction conditions. Preliminary experiments have shown that if Fe2+ is present in the Au/TiO2 cell and Fe3+ in the Au/CeO2 compartment, separated by a Nafion membrane, both photocatalysts perform oxygen generation. In contrast, if only Fe3+ salt is added to the Au/CeO2 chamber, hydrogen and oxygen are generated simultaneously in the cell containing Au/TiO2 and Au/CeO2 respectively. Figure 1 shows temporal evolution of hydrogen and oxygen for this photocatalytic system combining two semiconductors under visible light irradiation. Scheme 1. Diagram of water splitting by a Z-scheme system using Au/CeO2 as photocatalyst for oxygen generation, Au/TiO2 for hydrogen generation and Fe3+/Fe2+ as redox couple. Figure 1. ■ Hydrogen evolution using Au(0.25 wt%)/TiO2, □ Oxygen evolution using Au(0.25 wt%)/CeO2, under visible light irradiation In conclusion, we have found that the overall water splitting using visible light can be carried out combining Au/TiO2 and Au/CeO2 photocatalysts. References: 1C. Gomes Silva, R. Juàrez, T. Marino, R. Molinari and H. Garcìa, J. Am. Chem. Soc., 2011, 133 (3), pp 595-602 2A. Primo, T. Marino, A. Corma, R. Molinari and H. Garcìa, J. Am. Chem. Soc., 2011, 133 (18), pp 6930-693
Photocatalytic overall water splitting by combining gold nanoparticles supported on TiO2 and CeO2
MOLINARI, Raffaele;
2011-01-01
Abstract
Photocatalytic water splitting can play an important role for the generation of hydrogen. It has been recently found that gold nanoparticles acting as dyes enhance the photocatalytic activity of TiO2 in the visible region1. Also recently we have show that cerium nanoparticles of a small size can be a semiconductor for the photocatalytic oxygen generation from water and also in this case deposition of gold increases the photoresponse to the visible region2. In this previous report hydrogen and oxygen generation has been performed in the presence of sacrificial agent. Now we have combined the activity of both semiconductors in a Z-scheme device for the visible light overall water splitting. Scheme 1 illustrates the photocatalytic system and indicates the initial reaction conditions. Preliminary experiments have shown that if Fe2+ is present in the Au/TiO2 cell and Fe3+ in the Au/CeO2 compartment, separated by a Nafion membrane, both photocatalysts perform oxygen generation. In contrast, if only Fe3+ salt is added to the Au/CeO2 chamber, hydrogen and oxygen are generated simultaneously in the cell containing Au/TiO2 and Au/CeO2 respectively. Figure 1 shows temporal evolution of hydrogen and oxygen for this photocatalytic system combining two semiconductors under visible light irradiation. Scheme 1. Diagram of water splitting by a Z-scheme system using Au/CeO2 as photocatalyst for oxygen generation, Au/TiO2 for hydrogen generation and Fe3+/Fe2+ as redox couple. Figure 1. ■ Hydrogen evolution using Au(0.25 wt%)/TiO2, □ Oxygen evolution using Au(0.25 wt%)/CeO2, under visible light irradiation In conclusion, we have found that the overall water splitting using visible light can be carried out combining Au/TiO2 and Au/CeO2 photocatalysts. References: 1C. Gomes Silva, R. Juàrez, T. Marino, R. Molinari and H. Garcìa, J. Am. Chem. Soc., 2011, 133 (3), pp 595-602 2A. Primo, T. Marino, A. Corma, R. Molinari and H. Garcìa, J. Am. Chem. Soc., 2011, 133 (18), pp 6930-693I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
