A new photocatalytic water splitting system under visible light irradiation mimicking a Z-scheme mechanism in photosynthesis

2002 ◽  
Vol 148 (1-3) ◽  
pp. 71-77 ◽  
Author(s):  
Kazuhiro Sayama ◽  
Kazuaki Mukasa ◽  
Ryu Abe ◽  
Yoshimoto Abe ◽  
Hironori Arakawa
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Photocatalytic Water Splitting ◽  
Splitting System

Solar Hydrogen Production: Direct Water Splitting Into Hydrogen and Oxygen by New Photocatalysts Under Visible Light Irradiation

Solar Energy ◽  
2003 ◽  
Author(s):  
Hironori Arakawa ◽  
Zhigang Zou ◽  
Kazuhiro Sayama ◽  
Ryu Abe
Keyword(s):  
Quantum Yield ◽  
Solar Energy ◽  
Visible Light ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Solar Hydrogen ◽  
Solar Hydrogen Production ◽  
Natural Photosynthesis ◽  
Splitting System

The photocatalytic splitting of water into hydrogen and oxygen using solar energy is one of the most attractive renewable sources of hydrogen fuel. Therefore, considerable efforts have been paid in developing photocatalysts capable of using visible light, which accounts for about 43% of the solar energy. However such a photocatalyst has not been developed so far. We have developed a new Ni-doped indium-tantalum oxide photocatalyst, In1-xNixTaO4 (x = 0.0∼0.2), which induced direct splitting of water into stoichiometric amount of oxygen and hydrogen under visible light irradiation with a quantum yield of about 0.66% at 420.7 nm. We have also developed a new two-step water splitting system using two different semiconductor photocatalysts, Pt/WO3 photocatalyst for oxygen evolution and Pt/SrTiO3(Cr-Ta-doped) photocatalyst for hydrogen evolution, and a redox mediator, I−/IO3−, mimicking the Z-scheme mechanism of the natural photosynthesis. The quantum yield of this system was about 0.1% at 420.7nm. Both photocatalytic methods are the first examples for visible light water splitting system in the world.

Dye-Sensitized Photocatalyst System for Water Splitting Into H2 and O2 Under Visible Light Irradiation

Solar Energy ◽  
2004 ◽  
Author(s):  
Ryu Abe ◽  
Kazuhiro Sayama ◽  
Hironori Arakawa
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Energy Gap ◽  
H2 Production ◽  
Light Irradiation ◽  
Mixed Solution ◽  
Tio2 Photocatalysts ◽  
Dye Sensitized ◽  
Splitting System

H2 production from a water-acetonitrile mixed solution containing iodide electron donor was investigated over dye-sensitized Pt/TiO2 photocatalysts under visible light irradiation, as a part of water splitting system using iodide redox mediator. The rates of H2 evolution were decreased with the increase of the water ratio in the mixed solutions, because of the decrease in energy gap between the redox potential of I3−/I− and the HOMO levels of the dyes, which lowing the efficiency of electron transfer from I− to dye.

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