Effect of P/Ni molar ratio on the structure and hydrodesulfurization performance of nickel phosphide catalyst prepared by the solvothermal method

Abstract

A series of MCM-41-supported NixP catalysts was prepared by the solvothermal method using low-price triphenylphosphine as phosphorus material and tri-n-octylamine as coordinating solution-phase. They were characterized with X-ray diffraction, N2 sorption, CO sorption, X-ray photoelectron spectroscopy and transmission electron microscopy techniques. The effects of initial P/Ni molar ratio on their structures and hydrodesulfurization performances were investigated in a lab-scale continuous flow fixed-bed reactor by feeding 1% of dibenzothiophene (DBT) in decahydronaphthalene. It was shown that Ni12P5 was primarily formed with a small amount of Ni2P at the initial P/Ni molar ratio of 0.5. When the initial P/Ni molar ratio was higher than 0.5, pure Ni2P phase was generated, and its crystal size decreased, and thus, its dispersion increased with the increase of initial P/Ni molar ratio. At 613 K, 3.0 MPa, H2/oil volume ratio of 500, and weight hourly space velocity of 2.0 h−1, the DBT conversion nearly reached 100% on both the Ni-P(6)/MCM-41 and the Ni-P(10)/MCM-41 samples.