Thermochemical decomposition of water
Onuki, Kaoru; Noguchi, Hiroki
; Tanaka, Nobuyuki
; Takegami, Hiroaki
; Kubo, Shinji

Thermochemical water-splitting process decomposes water using thermal energy by operating high temperature endothermic reaction(s) and low temperature exothermic reaction(s) cyclically, with which free energy of water decomposition is produced. The so-called sulfur family processes, which utilize thermal decomposition of sulfuric acid as the high temperature endothermic reaction, have attracted lots of interest among the many processes proposed so far. The IS process represents the pure thermochemical sulfur family processes. The continuous hydrogen production by IS process was demonstrated in laboratory, and the materials of construction for the IS process have been screened by corrosion tests performed in the severe process environment. At present, application of membrane technologies and development of catalysts are under study to improve the hydrogen production performance. Also, development is underway of the chemical reactors made of candidate materials such as ceramics.