Sulfur tolerance improvement of Ni-YSZ anode by alkaline earth metal oxide BaO for solid oxide fuel cells

The anodic performances of Ni-Y ₂O ₃ stabilized ZrO ₂ (Ni-YSZ) modified by alkaline earth metal oxide BaO were investigated for solid oxide fuel cells operating in H ₂S-containing hydrogen fuels. The XRF and EDS results indicated that the amount of BaO was about 5%. The cell with BaO/Ni-YSZ anode exhibited almost constant peak power densities when the fuel was switched from wet hydrogen to 50 ppm H ₂S contaminated wet hydrogen and good stability in wet H ₂S-contained hydrogen fuels with H ₂S concentration gradually increased from 5 to 50 ppm. The EDS and XPS results demonstrated that no element S was detectable after sulfur poisoning testing. High water adsorption ability of BaO could be the primary reason for the high sulfur tolerance. The obtained results confirmed the previous conclusion that BaO/Ni interfaces can resist not only deactivation by coking but also sulfur poisoning of a conventional Ni-YSZ anode.