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Title: Active Phase of a Nickel Phosphide (Ni2P) Catalyst Supported on KUSY Zeolite for the Hydrodesulfurization of 4,6-DMDBT

Abstract

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 sitesmore » 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.« less

Authors:
; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930386
Report Number(s):
BNL-81108-2008-JA
Journal ID: ISSN 0926-860X; ACAGE4; TRN: US200904%%533
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Catalysis A: General; Journal Volume: 322
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; NICKEL PHOSPHIDES; CATALYTIC EFFECTS; HYDROGENATION; DESULFURIZATION; POLYCYCLIC SULFUR HETEROCYCLES; ZEOLITES; CATALYST SUPPORTS; national synchrotron light source

Citation Formats

Lee,Y., Shu, Y., and Oyama, S.. Active Phase of a Nickel Phosphide (Ni2P) Catalyst Supported on KUSY Zeolite for the Hydrodesulfurization of 4,6-DMDBT. United States: N. p., 2007. Web. doi:10.1016/j.apcata.2007.01.007.
Lee,Y., Shu, Y., & Oyama, S.. Active Phase of a Nickel Phosphide (Ni2P) Catalyst Supported on KUSY Zeolite for the Hydrodesulfurization of 4,6-DMDBT. United States. doi:10.1016/j.apcata.2007.01.007.
Lee,Y., Shu, Y., and Oyama, S.. Mon . "Active Phase of a Nickel Phosphide (Ni2P) Catalyst Supported on KUSY Zeolite for the Hydrodesulfurization of 4,6-DMDBT". United States. doi:10.1016/j.apcata.2007.01.007.
@article{osti_930386,
title = {Active Phase of a Nickel Phosphide (Ni2P) Catalyst Supported on KUSY Zeolite for the Hydrodesulfurization of 4,6-DMDBT},
author = {Lee,Y. and Shu, Y. and Oyama, S.},
abstractNote = {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.},
doi = {10.1016/j.apcata.2007.01.007},
journal = {Applied Catalysis A: General},
number = ,
volume = 322,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Ni2P catalysts supported on SiO2 and MCM-41 were prepared by temperature-programmed reduction (TPR), and the effect of the dispersion on catalyst structure and hydroprocessing performance was studied. The surface areas of the samples varied from low (Ni2P/SiO2-L, 88 m2 g?1) to high (Ni2P/SiO2-H, 240 m2 g?1), to very high (Ni2P/MCM-41, 487 m2 g?1), with corresponding Ni2P average crystallite sizes decreasing from 10.1 to 6.5 and 3.8 nm. X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) studies were used to obtain structural parameters for the supported Ni2P phase. The catalytic activity in hydrodesulfurization (HDS) was measured at 613 Kmore » and 3.1 MPa in a three-phase fixed bed reactor using a model liquid feed containing 4, 6-dimethyldibenzothiophene (4, 6-DMDBT) and quinoline in a tridecane solvent. At standard conditions using 500 ppm S as 4, 6-DMDBT, 6000 ppm S as dimethyldisulfide (DMDS), and 500 ppm N as quinoline, the catalytic activity followed the sequence Ni2P/MCM-41 > Ni2P/SiO2-H > Ni2P/SiO2-L, based on equal sites (230 ?mol) loaded in the reactor. In particular, Ni2P/MCM-41 gave an HDS conversion of 90%, which was much higher than that of a commercial Ni-Mo-S/Al2O3 catalyst which gave an HDS conversion of 68%, based on equal number of sites (230 ?mol) loaded in the reactor. The sites were counted by CO chemisorption for the phosphide and by low-temperature O2 chemisorption for the sulfide. EXAFS analysis of the samples confirmed the presence of two types of sites, tetrahedral Ni(1) sites and square pyramidal Ni(2) sites, with the latter growing in number in the same order as the reactivity Ni2P/MCM-41 > Ni2P/SiO2-H > Ni2P/SiO2-L, as the crystallite size decreased. From the selectivity to the direct desulfurization (DDS) product (dimethylbiphenyl) and the hydrogenation (HYD) products (methylcyclohexyltoluenes and dimethylbicyclohexyls) it is concluded that the Ni(1) sites are responsible for DDS while the Ni(2) are highly active sites for the HYD route.« less
  • The HDS properties of a series of Co xNi 2-xPy/SiO 2 catalysts have been investigated as a function of the Co/Ni molar ratio (for a fixed P/Me molar ratio) and of the P/Me molar ratio (for a fixed Co/Ni molar ratio). An oxidic precursor composition of Co 0.08Ni 1.92P 2.00 on the silica support yielded the bimetallic phosphide phase having the highest HDS activity, 34% higher than that of an optimized nickel phosphide catalyst prepared from an oxidic precursor having a composition of Ni 2.00P 1.60. X-ray photoelectron spectroscopy revealed Ni-rich Co xNi 2-xP y/SiO 2 catalysts to have surfacemore » enrichment of P (relative to Ni 2.00P 1.60/SiO 2 and Co 2.00P 1.00/SiO 2 catalysts) and to incorporate remarkably low amounts of S during HDS testing. The high activity of these Co xNi 2-xPy/SiO 2 catalysts is attributed to surface enrichment of P relative to nickel phosphide, which results in improved resistance to S incorporation under HDS conditions. Consistent with these findings and the solid-state chemistry evidence that suggests that Ni atoms in Ni-rich Co xNi 2-xPy/SiO 2 catalysts occupy disproportionately more pyramidal M(2) sites than tetrahedral M(1) sites, we conclude that the high site densities of these catalysts are due to Ni atoms in surface M(2) sites, which results in P-enriched surfaces that are resistant to site blockage due to S incorporation.« less
  • A Ni{sub 2}P catalyst supported on a high-surface area SiO{sub 2} (350 m{sup 2} g{sub -1}) was prepared by temperature-programmed reduction, and its structural and surface properties were studied. X-ray diffraction and extended X-ray absorption fine structure measurements were used to obtain structural parameters for the supported Ni{sub 2}P phase, and Fourier transform infrared (FTIR) analysis with the probe molecules CO and pyridine was carried out to characterize the surface properties. The catalytic activity was measured at 573 K and 3.1 MPa in a three-phase fixed-bed reactor for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) using a model liquid feed. At standardmore » conditions using 500 ppm S as 4,6-dimethyldibenzothiophene (4,6-DMDBT), 3000 ppm S as dimethyldisulfide, 200 ppm N as quinoline, and 1% tetralin in a tridecane solvent, the Ni{sub 2}P/SiO{sub 2} gave an HDS conversion of 85%, an HDN conversion of 100%, and a tetralin conversion of 37%, which were much higher than those of a commercial Ni-Mo-S/Al{sub 2}O{sub 3} catalyst, which gave an HDS conversion of 41%, an HDN conversion of 98%, and a tetralin conversion of 20% based on equal numbers of sites (240 {micro}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. The Ni{sub 2}P/SiO{sub 2} catalyst favored the hydrogenation (HYD) pathway for 4,6-DMDBT HDS to generate methylcyclohexyltoluene and dimethylbicyclohexane with a relative HYD selectivity of 95%. It also favored hydrogenation for tetralin to give decalin with a relative HYD selectivity of 89%. The Ni{sub 2}P/SiO{sub 2} catalyst also showed better resistance to N-compounds than the Ni-Mo-S/Al{sub 2}O{sub 3} catalyst. The FTIR spectra of adsorbed CO showed that the Ni site in the Ni{sub 2}P phase gave rise to considerable {pi}-back bonding, which was related to the high activity of the Ni{sub 2}P/SiO{sub 2} catalyst in the hydrogenation of aromatics. The FTIR spectra of adsorbed pyridine showed that the Ni{sub 2}P phase had a P{single_bond}OH group associated with Br{o}nsted acidity that was active for the protonation of N compounds. These results thus suggest that the supported Ni{sub 2}P catalyst has bifunctional properties that are beneficial for catalytic activity in hydroprocessing.« less
  • No abstract prepared.
  • An investigation has been made of planar catalysts with an active layer of framework nickel obtained by vacuum-depositing aluminum on a nickel substrate, annealing, and subsequent leaching of the intermetallide formed. Thin layers of framework nickel (of the orders of tenths of a micrometer) have a significantly more highly developed inner surface and specific activity than the average characteristics of a powder of Raney nickel.