Bioethanol fed directly to commercial solid oxide fuel cells

Solid oxide fuel cells (SOFCs) based on conventional nickel-yttria stabilized zirconia (Ni-YSZ) anodes can not be fed directly with organic fuels because of the associated formation of carbon deposits. This presentation explores a simple approach to solve such relevant limiting factor that affects the utilization of dry biofuels such as ethanol and glycerol directly fed in SOFCs. The approach consists in depositing a composite multifunctional electrocatalyst layer on the SOFC anode to work as an internal integrated fuel processor. A protective layer based on a composite made of Ni-modified perovskite and gadolinia-doped ceria is coated on a conventional SOFC anode based on Ni-YSZ. Beside the oxygen storage properties of ceria, the composite electrocatalyst is characterized by the presence of FeCoNiOx nanoparticles in the outer layers and surface basicity properties based on a Ruddlesden-Popper phase. Efficient dehydrogenation mechanism, carbon deposition-free cracking reactions and internal reforming assisted by a H2/H2O "shuttle mechanism" appear as the key steps involved in the direct oxidation of the biofuels at the modified SOFC anode.