Zeolite-supported Ni and Mo catalysts for hydrotreatments. 2. HRTEM observations
Calcined and sulfided Ni-Mo catalysts supported on ultrastable Y zeolite (USY), NaY zeolite, mordenite, and ZSM-5 were studied by high-resolution electron transmission microscopy (HRTEM) with selected-area electron diffraction (SAED) and energy-dispersive spectroscopy (EDS). Ni and Mo oxide aggregates were rarely observed in the USY-supported Ni-Mo catalyst, indicating that most of Ni and Mo may be incorporated into USY, e.g., supercavities and possibly sodalite cages. However, there were a large number of {alpha}-NiMoO{sub 4} aggregates of different particle sizes in NaY-, mordenite-, and ZSM-5-supported catalysts, and the mordenite-supported catalyst also contained MoO{sub 3} crystals. The {alpha}-NiMoO{sub 4} may be attached to the surface of substrates as individual particles or needle aggregates, it may be disseminated into mordenite particles, or it may even form an isolated sphere (in Ni-Mo/NaY) or a needle (in Ni-Mo/ZSM-5) aggregates. Thus, most of Ni and Mo in NaY-, mordenite-, and ZSM-5-supported catalysts preferentially formed aggregates, although some Mo may have been incorporated into NaY and ZSM-5. After sulfidation, small MoS{sub 2} aggregates containing some Ni were rarely but occasionally found on the surface of USY zeolite; however, there were a large number of such MoS{sub 2} aggregates on the surface of NaY. Separate and intergrown MoS{sub 2} and Ni sulfides aggregates were observed on the surface of mordenite and ZSM-5. The Ni sulfide might be identified by SAED and high-magnification images as troilite-like NiS and/or Ni{sub 9}S{sub 8}, but definitely not as NiS with millerite structure or Ni{sub 3}S{sub 2}. These results indicated that sulfidation does not extensively affect Ni and Mo that have been incorporated into the supercavity and/or sodalite cage of USY in calcined Ni-Mo/USY. The USY-supported Ni-Mo catalyst had a much higher hydrodesulfurization (HDS) activity than the other zeolite-supported catalysts.
- Research Organization:
- Los Alamos National Lab., NM (US)
- Sponsoring Organization:
- US Department of Energy
- OSTI ID:
- 20014530
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 189; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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