$\ce{CO2}$ into $\ce{CO + O2}$ is easier but you need a catalyst and about 1500C
http://www.rsc.org/chemistryworld/news/2008/january/03010801.asp
In short:
Fe3O2 is heated to 1500C driving off oxygen. The resulting FeO is moved to CO2 chamber where it absorbs oxygen from the CO2. Result is CO and cooled Fe3O2. Cycle repeats.
