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

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.

Solar Energy ◽  
2004 ◽  
Author(s):  
Ryu Abe ◽  
Kazuhiro Sayama ◽  
Hironori Arakawa

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.


2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.


2015 ◽  
Vol 3 (36) ◽  
pp. 18622-18635 ◽  
Author(s):  
Susanginee Nayak ◽  
Lagnamayee Mohapatra ◽  
Kulamani Parida

Dispersion of exfoliated CN over the surface of exfoliated LDH composite materials, and its photocatalytic water splitting under visible-light irradiation.


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