Fig. 7 shows the gas molar fractions measured with the QMS
during the 1st and 25th cycle for Fe80-160, LSF731, and
LSF-30Fe-Pec-P OCMs. Sharp initial carbon monoxide peaks at
the beginning of the reduction were due to valve changes and
backpressure in the CATLAB system and should be ignored. A mixture
of hydrogen and water was always obtained when the oxidation
period started and pure hydrogen was not detected in any
case.