Effects of Heat Treatment Temperature on the Physicochemical Properties and Catalytic Performance of Bulk Ni–Mo–W Catalysts

The present study investigates the effects of heat treatment temperature on the physicochemical properties of bulk granular Ni–Mo–W catalysts. A series of bulk catalysts were synthesized and characterized by X-ray diffraction analysis, low-temperature nitrogen adsorption/desorption, CHNS elemental analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy. To evaluate the catalytic activity in hydrodesulfurization and hydrodenitrogenation reactions, the catalyst samples were tested in hydrotreating of vacuum gasoil. It was found that the bulk granular catalysts calcined at 400°C and lower temperatures were mainly X-ray amorphous. In the samples calcined above 400°C, a nickel molybdate phase was predominant. In these samples, the content of an active sulfide phase after sulfidation was lower than that in the samples prepared from X-ray amorphous oxide precursors. The test data showed that the catalyst calcined at 300ºC exhibited the highest activity in the hydrodesulfurization of vacuum gasoil.