Direct Splitting of Water Under Visible Light Irradiation with an Oxide Semiconductor Photocatalyst
Photoreaction Control Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.Nature (Impact Factor: 41.46). 01/2002; 414(6864):625-7. DOI: 10.1038/414625a
The photocatalytic splitting of water into hydrogen and oxygen using solar energy is a potentially clean and renewable source for hydrogen fuel. The first photocatalysts suitable for water splitting, or for activating hydrogen production from carbohydrate compounds made by plants from water and carbon dioxide, were developed several decades ago. But these catalysts operate with ultraviolet light, which accounts for only 4% of the incoming solar energy and thus renders the overall process impractical. For this reason, considerable efforts have been invested in developing photocatalysts capable of using the less energetic but more abundant visible light, which accounts for about 43% of the incoming solar energy. However, systems that are sufficiently stable and efficient for practical use have not yet been realized. Here we show that doping of indium-tantalum-oxide with nickel yields a series of photocatalysts, In(1-x)Ni(x)TaO(4) (x = 0-0.2), which induces direct splitting of water into stoichiometric amounts of oxygen and hydrogen under visible light irradiation with a quantum yield of about 0.66%. Our findings suggest that the use of solar energy for photocatalytic water splitting might provide a viable source for 'clean' hydrogen fuel, once the catalytic efficiency of the semiconductor system has been improved by increasing its surface area and suitable modifications of the surface sites.
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- "Hydrogen fuel harnessing solar energy has drawn considerable interest, in order to solve energy crisis and global warming  . "
ABSTRACT: Quantum dot sensitized photoanodes have drawn much attention due to their high potential as efficient anodes for photoelectrochemical (PEC) water splitting or solar cells. However the photocorrosion of QDs is the crucial barrier for applications in these devices. The in situ analysis of photocorrosion is important in understanding its mechanism and also developing the possible solution for photocorrosion. In this study we have developed a novel, integrated analysis system for in situ measurements of photocorrosion and PEC performances. We have fabricated the CdSe/CdS/ZnO nanowire (NW) arrays on quartz crystal microbalance (QCM) as a platform for usage as PEC photoanodes and also mass analysis at the same time. The in situ measuring of photocurrents and mass changes were performed with continuous operation of PEC cells for CdSe/CdS/ZnO NWs photoanode. The study exhibited highly correlated tendency in photocurrent decrease and mass reduction, due to photocorrosion of CdSe/CdS/ZnO NWs. Also to improve the photostability of CdSe/CdS/ZnO NWs, applications of passivation and catalysts were studied and their effects were discussed. Our integrated in situ analysis system is highly applicable to various semiconductor sensitized systems.Sensors and Actuators B Chemical 12/2015; 221. DOI:10.1016/j.snb.2015.06.092 · 4.10 Impact Factor
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