Can H2S poison the surface of yttria-stabilized zirconia?

The adsorption and dissociation of H2S on the yttria-stabilized zirconia (YSZ) (111) surface are studied using the first-principles methods. It is found that H2S and SH species are bound weakly on the YSZ(111) surface. Sulfur atom is essentially immobile both into the YSZ bulk and along the surface. Instead, it is stably anchored on the O atop of the YSZ surface with the formation of the SO2− fragment. The nudged elastic band (NEB) calculations show that the formation of SH from H2S (H2S → SH + H) is very easy, while the presence of a co-adsorbed H would inhibit the further dissociation of SH. In contrast, the hydrogenation of the adsorbed sulfur is rather easy. It is concluded that H could inhibit the formation of sulfur, thus the sulfur poisoning of the YSZ surface would be prevented by hydrogen.