Water can be seperated into hydrogen and oxygen through chemical means, if it is done between 800 and 1000 degrees centigrade, using, and recycling, sulfur and iodine. These temperatures are currently difficult (expensive) to reach, but the next generation of nuclear reactors will be made to operate in this range specifically so that hydrogen can be made.
Details here:
http://www.world-nuclear.org/info/inf70.htm Quote:
In each of the leading thermochemical processes the high-temperature (800-1000°C), low-pressure endothermic (heat absorbing) decomposition of sulfuric acid produces oxygen and sulfur dioxide:
H2SO4 ==> H2O + SO2 + 1/2O2
There are then several possibilities. In the iodine-sulfur process iodine combines with the SO2 and water to produce hydrogen iodide which then dissociates to hydrogen and iodine. This is the Bunsen reaction and is exothermic, occurring at low temperature (120°C):
I2 + SO2 + 2H2O ==> 2HI + H2SO4
The HI then dissociates to hydrogen and iodine at about 350°C, endothermically:
2HI ==> H2 + I2
This can deliver hydrogen at high pressure.
The net reaction is then:
H2O ==> H2 + 1/2O2 |
There are other chemical reactions being researched.