TPD STUDY AND CARBAZOLE HYDRODENITROGENATION ACTIVITY OF NITRIDED MOLYBDENA-ALUMINA

The relationship between the activity and surface molybdenum species o f nitrided 12.5% MoO3/Al2O3 was studied in the hydrodenitrogenation (H DN) of carbazole at 573 K and 10.1 MPa total pressure. The surface mol ybdenum species were determined by the desorption of nitrogen gas duri ng TPD. The surface area of NH3-cooled Mo/Al2O3 nitrided at 773 and 11 73 K was decreased by 8% and 61% from 245 m(2) g(-1) of the fresh MoO3 /Al2O3, respectively. The NH3-cooled Mo/Al2O3 catalysts had slightly h igher surface area than the He-cooled catalysts. The HDN rate increase d with increasing nitriding temperature in the HDN of carbazole on the nitride catalysts. The NH3-cooled Mo/Al2O3 catalysts nitrided at 1173 K were the most active in carbazole HDN and the He-cooled catalyst ni trided at 773 K was the least. (C) 1998 Elsevier Science B.V. All righ ts reserved.