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 w ith initial surface areas near 200 m(2)/g. Pretreatment at 200-700 deg rees C in flowing H-2 yielded amorphous materials that retained the lo wer Mo oxidation state characteristic of metal clusters (Mo6S8). Highe r temperature pretreatment (800 degrees C) resulted in formation of th e corresponding Chevrel phase. The LaMoS materials prepared and pretre ated at the lower temperatures had similar thiophene and benzothiophen e HDS rates to those for Chevrel phases. After HDS reaction, the surfa ce areas of the catalysts were near 30-50 m(2)/g. (C) 1997 Elsevier Sc ience B.V.