New insight into the support effect on HDS catalysts: evidence for the role of Mo-support interaction on the MoS2 slab morphology

MoS2 catalysts were prepared on Al2O3, SiO2 and TiO2 support. On the oxidic forms, Raman and UV-vis characterizations show the strong Mo-TiO2 interaction and the weak Mo-SiO2 one that leads to a poorer Mo dispersion. MoS2 nanoparticles were then studied by TEM and adsorption of CO followed by infra-red spectroscopy which allows the distinction and quantification of the two stable edges namely the S- and M- edges. It appears that the slab morphology is strongly modified by the support nature: thus the stronger the MoS2-support interaction the higher the S-/M- edge ratio. Finally, MoS2 morphology impacts the catalytic activity in thiophene HDS: (1) an increase of the S-/M- edge ratio leads to the increase of the TOF value for Mo sulfided supported on Al2O3 and SiO2; (2) a specific behavior with high TOF value of mainly M-edge sites and strong hydrogenating properties is underlined for Mo/TiO2.