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.