Iron-Nickel Alloys for Carbon Dioxide Activation by Chemical Looping Dry Reforming of Methane

Chemical looping combustion is a clean combustion technology for fossil or renewable fuels. We have previously shown that the process can also be used to enable CO2 activation through reduction to CO with Fe oxygen carriers in so-called chemical looping dry reforming (CLDR). Although Fe shows good reactivity with CO2, its reactivity with methane as a fuel is low. In contrast, Ni is highly reactive for methane conversion but cannot be oxidized with CO2. Here, we demonstrate that Fe-Ni alloys combine the reactivities of each metal synergistically. By combining materials synthesis and characterization with reactive evaluation in multicycle CLDR operation, we demonstrate that relatively low amounts of Ni suffice to activate the carrier for methane conversion and that the presence of Fe enables the reoxidation of Ni with CO2. Moreover, the weak oxidant CO2 allows the controlled oxidation of the Fe-Ni alloy, which enables CH4 upgrading through syngas (CO+H-2) production.