Water splitting systems

Abe, R., Sayama, K., Domen, K., and Arakawa, H. (2001) A new type of water splitting system composed of two different Ti02 photocatalysts (anatase, rutile) and a IOj"/r shuttle redox mediator. Chemical Physics Letters, 344 (3-4), 339-344. 

Besides the subjects in Table 1, someone would list up radiolysis, which is the water-splitting system by radioactive rays. However, it belongs to a kind of photolysis, and has apprehensions that the produced hydrogen may carry the contaminated radioactivity. 

Ohta T (2001) A note on the gas-evolution of mechano-catalytic water splitting system. Int J Hydrogen Energy 26 401... 

Abe R, Sayama K, Domen K, Arakawa H (2001) A new type of water splitting system composed of two different Ti02... 

Before exaxning water splitting by sonophotocatalysis, photocatalysis of H202 was done because the photocatalytic process in the sonophotocatalytic water splitting system was assumed to be due to the decomposition of H202, as... 

Sayama et al.9) and Lincous et al.10) have proposed systems in which water is split by a combination of two photocatalytic and photochemical reactions. The present authors have also studied the water splitting system based on combined photocatalytic systems.u 15) Our goal is the construction of a water splitting system by mimicking the photosynthesis of green plants. 

Fig. 17.8 Energy levels for a water splitting system with a combination of two photocatalytic reactions for oxygen and hydrogen production.

In addition to the properties of micelles described above, vesicles, which are bilayer structures and can be considered to be model membranes, separate two distinct aqueous phases an entrapped or inner water pool and the bulk aqueous phase. In principle, therefore, electron transfer may be possible across the bilayer and the sites of hydrogen and oxygen production in a water splitting system can be separated spatially. 

Figure 10. An hypothetical model for a cyclic water splitting system, based on a semiconductor particle immobilized in a polymerized membrane and having access to both aqueous solutions on each side of the membrane. Specific and selective coating by catalysts leads to simultaneous and separate hydrogen and oxygen generation on each side of the polymerized membrane.

Sayama K, Mukasa K, Abe R, Abe Y, Arakawa H (2002) Photo-catalytic water splitting system into H2 and 02 under visible light irradiation mimicking a Z-scheme mechanism in photosynthesis. Solar Light Energy Conversion Team, Photoreaction Control Research Center, Advanced Industrial Science and Technology (AIST), Ibaraki, Japan... 

A New Photocatalytic Water Splitting System under Visible Light Irradiation Mimicking a Z-Scheme Mechanism in Photosyn thesis. See Entry 23 above. 349... 

Light Harvesting Units in Artificial Water Splitting Systems... 

This problem has been overcome only recently throu the development of bifunctional redox catalysts (1 ). The latter are distinguished by the fact that Pt and RUO2 are loaded onto the same mineral carrier particle. Colloidal Ti02 was the first material to be used as a siipport. It fulfills four different functions in the water splitting system (Figure 8) 1) It serves as... 

Semiconductors with band gaps smaller than 1.23 eV can be combined to drive water-oxidation/reduction processes separately via multiphoton processes. An example of fhis is fhe two-step water-splitting system using a reversible redox couple (A/R) shown in Figure 7 (Fujihara et al., 1988 Kudo et al., 1999 Sayama et al., 1987 Termakone and Wickramanayake, 1986) with two photocatalysts with different band-gap and band... 

From the foregoing discussion, it would appear that ordered assemblies have enormous potential for increasing the efficiency of water splitting systems since they can, under favourable circumstances, lead to efficient charge separation, although considerably more research in this area is required. In particular, the development of more efficient neutral electron transfer catalysts will assist electron transfer across bilayers. Bis(2,3 -diphenylditholato)nickel has been successfully employed as such a neutral electron transfer catalyst by dissolving it in diphenyl ether containing dicyclohexano-18-crown-6 supported in a millipore filter. Electron transfer occurs from EDTA... 

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