The hydrogen production in micromoles, calculated from the
integral of the hydrogen mole fraction versus time data, is depicted
in Fig. 8. Although the Fe80-160 OCM was more stable than the
iron oxide sub-micron powder, FeP, during the experiments performed
in the TGA and was capable of maintaining reactivity over
three cycles, a significant decrease in hydrogen production was
observed over 25 cycles in the CATLAB. With LSF731 or
LSF-30Fe-Pec-P, the hydrogen production remained constant after
the few cycles that were needed for stabilization. The hydrogen
production with LSF-30Fe-Pec-P in micromoles (367 lmol) during
the oxidation period of the 25th cycle was 8 times higher than the
production with Fe80-160 (46 lmol) and 4 times higher than the
production obtained with the LSF731 (93 lmol). The expected
available oxygen (Eq. (4)) for each material is equivalent to the
expected amount of hydrogen production on a weight basis. In
micromoles, the expected amount of hydrogen that could be
obtained using the LSF-30Fe-Pec-P is 299 lmoles. LSF-30Fe-Pec-P
produced 23% more hydrogen than expected. This indicates that
the perovskite is more reducible in the composite form. This may
be related to the synergetic behaviour observed in the TGA data