The generation of hydrogen by thermochemical reactions

Recently novel forms of energy carriers have increasingly come under discussion. One possible alternative to the currently employed systems is the utilization of hydrogen generated from water by thermal fission using available nuclear or solar energy. A series of circulatory processes, exploiting the ease of valency chance of e.g. metal halides, have been devised for the fission of water, so that it can be carried out at temperatures below 10000C. The chemistry, thermodynamics, and kinetics of the most widely developed thermochemical cyclic processes are briefly surveyed and the difficulties to be met with in the realization of such processes are outlined. (orig.)