Activity and structure of hydrotreating Ni, Mo, and Ni-Mo sulfide catalysts supported on {gamma}-Al{sub 2}O{sub 3}--USY zeolite
The catalytic hydrocracking (HC) of diphenylmethane (DPM) and hydrodesulfurization (HDS) of dibenzothiophene (DBT) over Ni, Mo, and Ni-Mo sulfide catalysts supported on a mixed ultrastable Y (USY) zeolite and gamma-Al{sub 2}O{sub 3} were studied. The catalysts were characterized using NH{sub 3} temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR diffuse reflectance spectroscopy (DRS), high-resolution transmission electron microscopy (HRTEM), and chemical composition analysis. Because addition of zeolite to a conventional alumina support improves acidity, Ni, Mo, and Ni-Mo catalysts supported on the combined supports had much higher HC activity. Ni was found to be uniformly distributed throughout the catalysts; however, Mo preferentially entered the structure of {gamma}-Al{sub 2}O{sub 3} or was accommodated as oxide aggregates on {gamma}-Al{sub 2}O{sub 3}, rather than associating with zeolite. Ni and Mo catalysts supported on {gamma}-Al{sub 2}O{sub 3}-USY zeolite were good HDS catalysts and showed a shallow maximum in catalytic activity at a NiO and MoO{sub 3} content of 5 mol%. The higher activity at this content occurred because Ni or Mo species had higher surface concentrations, higher dispersion, and were more easily sulfided. Ni-Mo catalysts supported on {gamma}-Al{sub 2}O{sub 3}-USY zeolite had high HDS activity, which showed a prominent maximum at a NiO/(NiO + MoO{sub 3}) ratio of about 0.4, because at this ratio the surface species of Ni and Mo were well dispersed and more easily sulfided to form a Ni-Mo-S phase responsible for the high HDS activity. The Ni-Mo catalysts supported on gamma-Al{sub 2}O{sub 3}-USY zeolite have slightly higher HDS activity than {gamma}-Al{sub 2}O{sub 3}-USY zeolite have slightly higher HDS activity than {gamma}-Al{sub 2}O{sub 3}-supported Ni-Mo catalysts.
- Research Organization:
- Los Alamos National Lab., NM (US)
- OSTI ID:
- 20003853
- Journal Information:
- Journal of Catalysis, Vol. 188, Issue 1; Other Information: PBD: 15 Nov 1999; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
Similar Records
Zeolite-supported Ni and Mo catalysts for hydrotreatments. 1: Catalytic activity and spectroscopy
Characterization of preparation factor influence on Ni-Mo/Al/sub 2/O/sub 3/ hydrotreating catalysts