Sr2Fe2-XMoXO6 double perovskites as electrocatalysts for oxidative dehydrogenation of ethane: Effect of B-site stoichiometry

The oxidative dehydrogenation of ethane (ODHE) was investigated using a solid oxide electrocatalytic cell with Sr2Fe2-XMoXO6-& delta; (SFM) double perovskite as the anode electrocatalyst. As shown in the XRD patterns, SFM perovskites maintained their cubic structure upon modifying the B-site ratios of Mo and Fe. Increasing the Mo content of the perovskite structure resulted in a lower water signal intensity at low temperatures in TPR profiles, indicative of moderate oxygen transport through the perovskite structure. Because Mo-O bonds are stronger than Fe-O bonds, the electrical conductivity of SFM perovskites decreased with increasing Mo content. When operated at 100 mA cm-2, ODHE activity improved four times compared to open circuit voltage, resulting in 16.1% conversion of C2H6 and 83.1% selectivity to C2H4. It has been demonstrated that oxygen ions provided by perovskite lattices were the key species involved in activating C2H6 based on the in-situ DRIFTS experiments. The SFM perovskite with higher Mo content showed the highest conversion and selectivity due moderate oxygen ion mobility and fast desorption of C2H4.