Active Phase of a Nickel Phosphide (Ni2P) Catalyst Supported on KUSY Zeolite for the Hydrodesulfurization of 4,6-DMDBT
Ni{sub 2}P catalysts supported on potassium ion-exchanged ultrastable Y zeolites (KUSY) were prepared by temperature-programmed reduction (TPR), and the effect of Ni{sub 2}P loading and initial Ni/P ratios on the hydroprocessing performance was studied. X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) were used to obtain structural parameters. Transmission electron microscopy (TEM) analysis showed that the KUSY-supported Ni{sub 2}P samples consisted of nanoparticles, which were likely situated in the mesoporous cavities or the external surfaces of the zeolite crystals. The catalytic activity was measured at 613 K and 3.1 MPa in a three-phase fixed bed reactor for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) using a model liquid feed containing 500 ppm S as 4,6-dimethyldibenzothiophene (4,6-DMDBT), 500 ppm N as quinoline, and 3000-6000 ppm S as dimethyldisulfide (DMDS). Partial exchange with K enhanced the catalytic activity for the HDS of 4,6-DMDBT and resistance to N-compound inhibition. The Ni{sub 2}P/KUSY had high activity with an HDS conversion of 99%, and an HDN conversion of 100%, which were much higher than those of a commercial Ni-Mo-S/Al{sub 2}O{sub 3} catalyst with an HDS conversion of 80% and HDN conversion of 100%, based on equal sites (240 {mu}mol) loaded in the reactor. The sites were counted by CO chemisorption for the phosphide and by low-temperature O{sub 2} chemisorption for the sulfide. Deficiency of P in the Ni{sub 2}P resulted in deactivation, probably due to susceptibility to sulfidation. EXAFS analysis of the catalysts showed that the addition of extra P led to an increase in Ni-P coordination with lengthening of Ni-Ni bond distances, resulting in a high and stable catalytic activity.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 930386
- Report Number(s):
- BNL-81108-2008-JA; ACAGE4; TRN: US200904%%533
- Journal Information:
- Applied Catalysis A: General, Vol. 322; ISSN 0926-860X
- Country of Publication:
- United States
- Language:
- English
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