Transition Metal Phosphide Hydroprocessing Catalysts: A review

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Catalysis Today

DOI:https://doi.org/10.1016/j.cattod.2008.09.019· OSTI ID:980657

Oyama, S; Gott, T; Zhao, H; Lee, Y

The diminishing quality of oil feedstocks coupled with increasingly more stringent environmental regulations limiting the content of sulfur in transportation fuels have given rise to a need for improved hydroprocessing technology. This review begins with a summary of the major improvements in hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts and processes that have been reported in recent years. It then describes a new class of hydroprocessing catalysts, the transition metal phosphides, which have emerged as a promising group of high-activity, stable catalysts. The phosphides have physical properties resembling ceramics, so are strong and hard, yet retain electronic and magnetic properties similar to metals. Their crystal structures are based on trigonal prisms, yet they do not form layered structures like the sulfides. They display excellent performance in HDS and HDN, with the most active phosphide, Ni{sub 2}P, having activity surpassing that of promoted sulfides on the basis of sites titrated by chemisorption (CO for the phosphides, O{sub 2} for the sulfides). In the HDS of difficult heteroaromatics like 4,6-dimethyldibenzothiophene Ni{sub 2}P operates by the hydrogenation pathway, while in the HDN of substituted nitrogen compounds like 2-methylpiperidine it carries out nucleophilic substitution. The active sites for hydrogenation in Ni{sub 2}P have a square pyramidal geometry, while those for direct hydrodesulfurization have a tetrahedral geometry. Overall, Ni{sub 2}P is a promising catalyst for deep HDS in the presence of nitrogen and aromatic compounds.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 980657
• Report Number(s): BNL--93575-2010-JA
• Journal Information: Catalysis Today, Journal Name: Catalysis Today Journal Issue: 1-2 Vol. 143; ISSN 0920-5861; ISSN CATTEA
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
36 MATERIALS SCIENCE
AROMATICS
CATALYSTS
CERAMICS
CHEMISORPTION
CRYSTAL STRUCTURE
FUELS
GEOMETRY
HYDROGENATION
MAGNETIC PROPERTIES
METALS
NITROGEN
NITROGEN COMPOUNDS
OILS
PERFORMANCE
PHOSPHIDES
PHYSICAL PROPERTIES
PRISMS
RISE
SULFIDES
SULFUR
TRANSITION ELEMENTS
national synchrotron light source