Synthesis, characterization, and hydrotreating activity of several iron group transition metal phosphides

Xianqin Wang, Paul Clark, S. Ted Oyama

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291 Scopus citations

Abstract

A series of iron, cobalt, and nickel metal phosphides of chemical formula Fe2P, CoP, and Ni2P with specific surface areas of around 3 m2 g-1 were synthesized by means of temperature-programmed reduction (TPR) of the corresponding phosphates. These phosphides were also successfully prepared in dispersed form on a silica support (90 m2 g-1) for use as catalysts. The phase purity of these materials was established by X-ray diffraction (XRD), and surface properties were determined by N2 BET specific surface area (Sg) measurements and CO uptake determinations. The activity of the silica-supported catalysts in hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) was evaluated in a three-phase trickle-bed reactor using a model liquid feed containing 2000 ppm nitrogen as quinoline, 3000 ppm sulfur as dibenzothiophene, 500 ppm oxygen as benzofuran, 20 wt% aromatics as tetralin, and balance aliphatics as tetradecane. The reactivity study showed that the HDS activity sequence for the three samples was Ni2P/SiO2>CoP/SiO2>Fe2P/ SiO2, while the HDN activity followed the sequence CoP/SiO2>Ni2P/SiO2>Fe2P/ SiO2. Compared with a commercial Ni-Mo-S/γ-Al2O3 catalyst, Ni2P/SiO2 had a higher HDS activity (90 vs 76%), but a lower HDN activity (14 vs 38%), based on equal sites loaded in the reactor. The sites were determined by CO chemisorption for the phosphide and low-temperature O2 chemisorption for the sulfide. XRD and X-ray photoelectron spectroscopy characterizations of the spent catalysts indicated that the Ni2P/SiO2 catalyst was tolerant of sulfur.

Original languageEnglish (US)
Pages (from-to)321-331
Number of pages11
JournalJournal of Catalysis
Volume208
Issue number2
DOIs
StatePublished - 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Physical and Theoretical Chemistry

Keywords

  • CoP
  • FeP
  • Hydrodenitrogenation
  • Hydrodesulfurization
  • NiP
  • Transition metal phosphides

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