Pathways for H₂ Activation on (Ni)-MoS₂ Catalysts

The activation of H₂ and H₂S on (Ni)MoS₂/Al₂O₃ leads to the formation of SH groups with acid character able to protonate 2,6-dimethylpyridine. The variation in concentrations of SH groups induced by H₂ and H₂S adsorption shows that both molecules dissociate on coordinatively unsaturated cations and neighboring S^2-. In the studied materials, one sulfur vacancy and four SH groups per 10 metal atoms exist at the active edges of MoS₂ under the conditions studied. H₂-D₂ exchange studies show that Ni increases the concentration of active surface hydrogen by up to 30% at the optimum Ni loading, by increasing the concentration of H₂ and H₂S chemisorption sites.