Thermochemical Water or Carbon Dioxide Splitting

In the previous discussion, in all processes the reduction of the oxygen carrier and the removal of its (lattice) oxygen were always forced by the fuel, which in the previous cases was methane and occasionally carbon monoxide. One could think of a process utilizing reversibly oxidized and reduced carriers where the reduction (oxygen removal) of the carrier takes place by heating at elevated temperatures without the presence of a fuel in reactor 2. The reaction that takes place under such conditions in reactor 2 can be written as 

When this reaction is combined with reactions (37.6) or (37.7) that take place in reactor 1, then the process formed is the thermochemical water or carbon dioxide splitting, provided the necessary heat for the reaction is supplied by solar energy. In that sense, the two-step thermochemical water or carbon dioxide splitting by redox oxide pairs, although as an idea was pubhshed and 

---