3. Numerous oxygen-carrying materials tested

It is difficult to find an oxygen-carrying material that performs well on criteria as varied as reactivity with the fuel, chemical and mechanical integrity, reasonable cost, etc. Moreover, low-cost natural ores are even more complex, as they are often inhomogeneous and chemically impure.

This section provides a summary of the many materials studied, both synthetic and natural, which present interesting characteristics for playing the role of oxygen carrier in "Chemical Looping" processes.