Silica-Encapsulated Fe2o3 Oxygen Carriers for Selective Chemical Looping Combustion of Hydrogen

Methane dehydroaromatization (MDA) combined with chemical looping (CL) combustion of hydrogen can overcome the MDA thermodynamic constraints conventionally limiting conversion. Development of selective hydrogen-oxidation oxygen carriers in the presence of aromatics in the CL is key to improve MDA performance in the coupled reaction system. Here we show that a novel oxygen carrier (silica-encapsulated Fe 2 O 3 with Fe/Si mole ratio of 1.2) yields high overall methane conversion (49%) and aromatics yield (up to 51%) during 4 hours of recirculating a stream in the developed system. A silica layer encapsulating Fe 2 O 3 favors hydrogen transport and oxidation, preventing aromatics diffusing to the Fe 2 O 3 surface. A strong interaction between Fe and silica in a well-encapsulated structure can provide facile hydrogen conversion without full depletion of iron oxides by forming iron silicates. The silica-encapsulated iron oxide particles can be reoxidized in air after depletion of its oxidative capacity.