The effect of a ceria coating on the H₂S tolerance of a molten carbonate fuel cell

To enhance the performance of anodes in molten carbonate fuel cells (MCFCs), in terms of their sulfur tolerance, we modified the surface characteristics of a conventional Ni-10 wt% Cr anode through dip coating using a ceria sol. The performance of the ceria-coated anode was 0.4 V higher than that of the uncoated anode when H₂S (80 ppm) was introduced under a current density of 150 mA cm^-2 for 180 h. H₂S acted as a poison of the non-modified Ni electrode, regardless of its operating conditions, to form Ni₃S₂, which caused the voltage drop. The ceria-coated anode had the ability to suppress such a voltage drop because ceria can react with H₂S to form Ce₂O₂S. Our results suggest that the presence of a CeO₂ coating layer can reduce the degree of sulfur poisoning of the anode under the operating conditions - e.g., a reducing atmosphere and a high temperature - experienced by MCFCs.