Adsorption and oxidation of sulfur dioxide on the yttria-stabilized zirconia surface: ab initio atomistic thermodynamics study

• SO2 is adsorbed either as a molecule or forms SO2−3 species on YSZ surface.
• There exist other sulfate (SO2−4) species on the very active YSZ+O surface.
• All the formed SOx (with x=2–4x=2–4) species are of a poisoning nature for the surfaces.
• The formation and transformation of oxidized species depends on ambient conditions.
• The YSZ+O surface is more susceptible to sulfur-poison than the YSZ surface.

The interaction of SO2 with the yttria-stabilized zirconia (YSZ) (111) and oxygen-enriched YSZ (111) (YSZ+O) surface is investigated using the first-principles method based density functional theory (DFT). It is found that SO2 is adsorbed either as a molecule or forms SO2−3 species with new SO bonds to a surface oxygen on the YSZ (111) surface. In addition, there exist other species, e.g., SO3 and SO2−4 on the very active YSZ+O (111) surface. Using the ab initio atomistic thermodynamics method, we present a detailed analysis on the stability of the SO2YSZ/YSZ+O system as a function of the ambient conditions.