Zeolite-supported Ni and Mo catalysts for hydrotreatments. 1: Catalytic activity and spectroscopy
- National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan). Dept. of Surface Chemistry
- Los Alamos National Lab., NM (United States). Chemical Sciences and Technology Div.
The catalytic hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrocracking (HC) of decalin, tetralin, and diphenylmethan (DMP) over Ni-Mo sulfide catalysts supported on ultrastable Y-type (USY) zeolite have been studied. The catalysts are characterized using NH{sub 3} temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), UV-vis-NIR diffuse reflectance spectroscopy (DRS), and Na and Al K-edge X-ray absorption near-edge structure (XANES). Ni-Mo sulfide catalyst supported on USY zeolite has an unusually high catalytic activity for the hydrotreating reactions of the model compounds compared with other zeolites and their supported catalysts. NH{sub 3} TPD shows the presence of a strong acid site at about 430 C in USY zeolite and its supported Ni-Mo catalyst, which is dominantly characterized by Broensted acidity. The surface concentrations of Ni and Mo in both calcined and sulfided Ni-Mo/USY zeolite catalysts are very low, indicating that the Ni and Mo phases are present in the crystal structure of USY zeolite. The diffuse reflectance spectra of calcined Ni-Mo/USY catalyst show that Mo is dominantly four-coordinate with oxygen and Ni is six-coordinate, consistent with the Ni and MO species being present in the crystal structure of USY zeolite. Al K-edge XANES spectra of calcined Ni-Mo/USY catalyst also indicate the presence of extra-framework Al, and the content of the extra-framework Al is much higher in Ni-Mo/USY than in Ni-Mo/NaY catalyst. However, there is no evidence that the extra-framework Al contributes to the acidity and the increased catalytic activity. Thus, the high catalytic HDS and HC activities of Ni-Mo/USY compared with other zeolites and their supported Ni-Mo catalysts are attributed to the synergistic effect between the strong Broensted acid sites and the Ni and Mo sulfide phases in the sodalite cage and/or supercage of USY zeolite.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 338551
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 182; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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