The effect of the oxidation state of molybdenum on the catalytic hydrodesulfurization (HDS) of thiophene was investigated using a series of lead-lutetium Chevrel phases. Polycrystalline catalysts were prepared with compositions of PbMo6.2S8, Lu1.2xPbMo6S8 for 0 < x ≤ 0.2, and Lu1.2x Pb1-xMo6S8 for 0.2 < x ≤ 1. Fresh and used (10-h thiophene reaction) catalysts were characterized by X-ray powder diffraction, laser Raman spectroscopy, and X-ray photoelectron spectroscopy. Bulk structures and molybdenum oxidation states were found to be stable. HDS activity could be related to the molybdenum formal oxidation state: the maximum rate of thiophene HDS was observed for catalysts having "reduced" oxidation states (compared to MoS2). All Chevrel phase catalysts demonstrated low activity for 1-butene hydrogenation.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry