Promoted methane conversion to syngas over Fe-based garnets via chemical looping

Fe-based oxygen carries (OCs) have attracted wide attention due to the low cost and environmental compatibility for chemical looping methane partial oxidation. However, they usually suffer from low CH 4 reactivity mainly due to insufficient synergy between catalytic CH 4 activation and lattice oxygen mobility. In this work, Fe ions with different amount were incorporated into a novel garnet structure (Y 3 Fe x Al 5-x O 12 ), which exhibited drastically increased CH 4 conversion with reduction time. This resulted from in-situ formed Fe 0 sites at the early stage of reduction, which led to a more efficient reaction route involving methane catalytic decomposition on Fe 0 and the resulted carbon oxidation easier by lattice oxygen, compared with methane directly oxidized by OCs. Moreover, the amount of Fe ions in garnet influenced surface exposed Fe 0 sites and oxygen mobility, inducing Y 3 Fe 2 Al 3 O 12 performed the best with almost 94 % methane conversion thanks to the combined advantages of larger surface exposed Fe 0 and higher lattice oxygen mobility.