Preparation mechanism and hydrodenitrogenation performance of nickel phosphide catalyst

Thermal decomposition of nickel hypophosphite precursor into nickel phosphide (Ni₂P) was studied using thermogravimetry-mass spectrometry analysis. The results indicated that nickel ion (Ni²⁺) influenced the decomposition pathway of hypophosphite, because it might catalyze the reaction of hypophosphite to produce PH₃ at lower temperature. Silica-supported Ni₂P catalysts with different loadings were prepared and characterized using X-ray diffraction, N₂ adsorption-desorption, and high resolution transmission electron microscopy. It was indicated that Ni₂P was well dispersed on the support with a particle size of 5～8 nm. The catalytic performance of as-prepared catalysts was evaluated in a fixed-bed reactor for hydrodenitrogenation of quinoline. Under the reaction temperature of 360℃, hydrogen pressure of 2.0 MPa, LHSV of 2.0 h^-1, and H₂/oil volume ratio of 500:1, the conversion of quinoline over Ni₂P(20%)/SiO₂ catalyst reached 41.5%.