The performance of a solid oxide fuel cell based on BaTiO3 anode improves when H2 and CH4 containing H2S are employed as fuels. In this work, density functional theory calculations were conducted to reveal the origin behind this boost in performance. Our calculations predicted that the sulfidation of the BaTiO3(001) surfaces is possible via different reaction pathways. For the hydrogen oxidation reaction, the presence of sulfur led to the formation of different molecular entities
thus alternative sequences of elementary steps for the reaction to proceed came to light, and no significant detrimental effect was noticed on the adsorption of the species involved. On the other hand, for the methane sequential dissociation, no detrimental effect on the methane activation and the promoted scission of some C-H bonds may be responsible for the mentioned boost in performance.