Direct Splitting of Water Under Visible Light Irradiation with an Oxide Semiconductor Photocatalyst
ABSTRACT 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.
Full-textDOI: · Available from: Hironori Arakawa, Sep 29, 2015
- SourceAvailable from: Jin Yuan Zhou
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- "Thus, it is an urgent to find a new way for hydrogen production . Since Fujishima and Honda reported the successful photoelectrochemical (PEC) water splitting in 1972 , the extensive attention has been focused on semiconductor photocatalytic hydrogen production     . The most studied photocatalysts are metal oxide semiconductors, such as TiO 2     , ZnO  , α-Fe 2 O 3      and WO 3   due to their favorable band-edge position, excellent chemical stability, large photocorrosion resistance and low cost. "
ABSTRACT: Here, we present a kind of SnO2 nanowires/TiO2 nanoneedles/CdS quantum dots multi-heterojunction structure. In this rational heterojunction structure, three dimensional SnO2 nanowires were directly grown on conductive fluorine doped tin oxide (FTO) glass by chemical vapor deposition method and served as the faster electron transport network for highly efficient photoelectrochemical system. Moreover, after artful design of branched TiO2 nanoneedles on this network and then sensitized by CdS quantum dots, a multi-heterojunction structure of SnO2/TiO2/CdS was formed. This novel three dimensional multi-heterojunction structure exhibited remarkable performances on photoelectrochemical hydrogen production. The photocurrent density is as high as 8.75 mA cm−2 at a potential of 0 V vs. saturated calomel electrode (SCE) by using the optimized conditions. More impressively, the photocurrent density is more than 4 times larger than that of single SnO2–TiO2 heterojunction (1.72 mA cm−2) at 0 V vs. SCE.Solar Energy Materials and Solar Cells 10/2015; 141. DOI:10.1016/j.solmat.2015.05.026 · 5.34 Impact Factor
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- "Recently, TiO 2 have attracted considerable attention due to its various applications such as dyes for sensitized solar cells, the photocatalytic splitting of water for hydrogen production, the selective synthesis of organic compounds, air purification and the degradation of organic and inorganic pollutants        . "
ABSTRACT: Nanocrystalline TiO2 and Si-doped TiO2 samples were prepared by solvothermal and sol-gel methods. Before the characterization and photocatalytic test, the thus-obtained powder and gel were calcined under different atmospheric gas flows (O2, air, and N2). The physiochemical properties of the samples were determined using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), electron spin resonance (ESR), transmission electron microscope (TEM), energy dispersive x-ray spectrometer (EDX) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated by the degradation of methylene blue (MB) dye under UV and visible light irradiation. The solvothermal-made N2-treated TiO2 nanocatalyst showed the highest photocatalytic activity under both UV and visible light irradiation. The addition of Si resulted in the formation of partial monolayer of Si on TiO2 nanocatalyst and an increase of the anatase phase stability. The ESR and XPS results reveal that the calcining atmosphere affected the distribution concentration of surface and interface species in TiO2 and Si-doped TiO2, such as surface oxygen and Ti3+ sites, thus improving photocatalytic activity. The increasing of anatase phase stability and the formation of Ti3+ sites due to N2-treated and Si-doped TiO2 nanocatalyst promoted the photocatalytic activity of MB degradation.Ceramics International 06/2015; DOI:10.1016/j.ceramint.2015.05.104 · 2.61 Impact Factor
- "This view has been supported by a recent comprehensive review on hydrogen generation . The urgent need to develop hydrogen technologies has resulted in much R&D activity on materials for solar hydrogen     . The PEC solar cells can be improved by the use of novel materials to increase the conversion efficiency of solar energy into chemical energy      . "
Dataset: Review 2009