Metal cluster hydrodesulfurization catalysts based on ternary lanthanum molybdenum sulfides

Hydrodesulfurization (HDS) catalysis by a new group of reduced ternary molybdenum sulfides involving Mo6S8 clusters has been investigated. A low temperature synthesis route was used to produce LaMoS materials with initial surface areas near 200 m(2)/g. Pretreatment at 200-700 degrees C in flowing H-2 yielded amorphous materials that retained the lower Mo oxidation state characteristic of metal clusters (Mo6S8). Higher temperature pretreatment (800 degrees C) resulted in formation of the corresponding Chevrel phase. The LaMoS materials prepared and pretreated at the lower temperatures had similar thiophene and benzothiophene HDS rates to those for Chevrel phases. After HDS reaction, the surface areas of the catalysts were near 30-50 m(2)/g. (C) 1997 Elsevier Science B.V.