CVD preparation of alumina-supported tungsten nitride and its activity forthiophene hydrodesulfurization

Tungsten nitride was synthesized on gamma-alumina pellet and quartz plate u sing the chemical vapor deposition (CVD) method in a stream of WCl6, NH3, H -2 and Ar gases at 700 degrees C under reduced pressure. The effects of the supports, catalyst preparation and pretreatment on the activities of alumi na-supported tungsten nitrides for the hydrodesulfurization (HDS) of thioph ene at 300 degrees C and atmospheric pressure were discussed. The alumina-s upported tungsten nitride catalyst prepared by the CVD method had a surface area of 161 m(2)g(-1). The micropore distribution of the alumina-supported CVD catalyst varying with deposition time was analyzed by Dolimore-Heal me thod. The surface area of the CVD catalysts depended on the supports such a s alumina, quartz, and zeolite Y. Thiophene HDS showed a constant activity of the CVD/alumina catalysts deposited for 30 and 60 min, but the 90 min-de posited catalyst was activated after the decreased activity at an initial s tage. (C) 1999 Elsevier Science B.V. All rights reserved.