Oxidative dehydrogenation of ethanol on Fe2(MoO4)3 – following structural dynamics during EtOH switching

Recently, iron molybdate (Fe2(MoO4)3, noted as FMO) has been considered as the promising thermocatalyst in oxidative dehydrogenation (ODH) of ethanol (EtOH) with high selectivity towards acetaldehyde. However, the exact role of Fe in the redox chemistry of the EtOH ODH is not clear so far. By in situ synchrotron based Mössbauer spectroscopy (SMS) we would like to probe how the bulk Fe in FMO is changing under reaction condition. We recently performed our first in situ SMS beamtime at ID 14, ESRF (CH-7299), to follow (sub)surface and bulk structural change in FMO under reductive conditions by coupling Raman spectroscopy and SMS. However, in case of switching between reactive and oxidative condition the sensitivity was insufficient (1% change in SMS vs +100% in Raman). Based on this, we like to repeat the reactive/oxidative switching experiments using a more favorable surface to bulk ratio for our standard sample as well as two further materials that obtain interesting catalytic data.