Water splitting processes

Trester, P.W. and Staley, H.G., Assessment and investigation of containment materials for the sulfur-iodine thermochemical water-splitting process for hydrogen production, Gas Research Institute report GRI-80/0081,1981. 

Sulfur-Iodine Thermochemical Water-Splitting Process... 

A portion of the supplied thermal energy is expelled with the products. The overall water splitting process, see Fig. 2.6, in general requires both heat and work input. In Fig. 2.6 qr represents the heat energy supplied at high temperature Tr, qo represents the heat rejected at lower temperature To, and Wi is the useful work input, if any, for the process. The enclosed region contains only water, or water and materials involved in different... 

Fig. 2.6 General representation of the thermochemical water splitting process...

As the water splitting process is cyclic (reversible behavior shown by dotted lines in Fig. 2.6) it has limitations imposed by second law of thermodynamics [60]. Hence the operating temperatures Tr and To are crucial in determining the thermal efficiency of the process. In a water splitting process using both heat and work inputs, the thermal efficiency in general is defined as [60,61]... 

Funk JE (1976) Thermochemical production of hydrogen via multistage water splitting processes, Int J Hydrogen Energy 1 33-43... 

Based on the EPR, ENDOR, ESEEM and some other spectroscopic results models for Yz function in PS II have been developed (see references 385, 386 for recent reviews). There seems to be consensus that this amino acid is involved in proton-coupled electron-transfer. As proton acceptor His (Dl-190) was identified which is also found to be close to Yz in the recent X-ray structure.19 The postulated direct involvement of Yz in the water splitting process as a hydrogen atom abstractor or in separate or coupled proton/electron-transfer is still controversially discussed.385 386... 

After the initial enthusiasm created by several publications on this subject, the catalytic properties of dithiolenes in photochemical water-splitting processes are now somewhat less exciting. Nevertheless, this area continues to receive attention, both from the experimental21 1"218 and the theoretical140 side. 

BurdaK. Bader K. P. Schmid G. H. lsO isotope effect in the photosynthetic water splitting process. Biochim. Biophys. Acta, Bioenerg. 2003, 1557, 77-82. 

O Brien, J.E. (2008b), Thermodynamic Considerations for Thermal Water Splitting Processes and High-temperature Electrolysis , 2008 ASME International Congress and Exposition, Boston, MA, USA, November, paper IMECE2008-68880. 

Leybros, J., P. Carles, J-M. Borgard (2009), Countercurrent Reactor Design and Flow Sheet for Iodine-sulfur Thermochemical Water Splitting Process , Int. J. of Hydrogen Energy, forthcoming. 

Funk, J.E. (1976), Thermochemical Production of Hydrogen via Multistage Water Splitting Processes , Int.J. Hydrogen Energy, 1, 33-43. 

Tennessee. He worked on the processing and fabrication of fresh and irradiated nuclear fuels materials at Oak Ridge National Laboratory and at the General Atomic Company for 20 years. For the past five years he has done conceptual and bench-role process design for hydrogen production processes, principally for thermochemical water-splitting processes. 

Carbon implications. If nuclear energy is used in the short term as the heat source in the SMR process, the result would be to reduce C02 emissions by nearly 40 percent. If one of the water-splitting processes is used, whether via a thermochemical process or an electrolysis approach, there will be no CO or C02 emissions. 

In Eq. 2, F is the Faraday constant (96485 C mof ) and the negative sign denotes the thermodynamically non-spontaneous nature of the water splitting process. The actual voltage required for electrolysis will depend on the fugacities of the gaseous products in Reaction 1 as well as on the electrode reaction kinetics (overpotentials)... 

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