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

Tungsten nitride was synthesized on gamma-alumina pellet and quartz plate using 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 alumina-supported tungsten nitrides for the hydrodesulfurization (HDS) of thiophene at 300 degrees C and atmospheric pressure were discussed. The alumina-supported 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 method. The surface area of the CVD catalysts depended on the supports such as 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-deposited catalyst was activated after the decreased activity at an initial stage. (C) 1999 Elsevier Science B.V. All rights reserved.