Nuclear (water splitting)

Thermochemical water splitting uses thermal energy (i.e. pure thermochemical cycles) or thermal and electrical energy (i.e. hybrid thermochemical cycles) and cycles of chemical reactions to produce hydrogen and oxygen from water. Nuclear and concentrated solar can be used for the generation of these high temperatures. Over 360 thermochemical processes are known and have been described. The down selection from all these processes is done by a reduced number of chemical steps (ideally 2, usually 3 to maximum 4), the use of heat at value that can provide nuclear reactors (850°C is a maximum, 650-550°C is be preferred), and the preference (if possible) to liquid and gas products used in all cycles. Today ten or so cycles are still investigated and being compatible with nuclear heat.
The concept of using thermochemical cycles for hydrogen production started with the first patent in the early 1920s on a two-step cycle, but it was not until the early 1960s that several research activities started to tackle the topic.