Effect of preparation methods on the structure and naphthalene hydrogenation performance of Ni2P/SiO2 catalyst

Abstract Ni2P/SiO2 catalysts were prepared by temperature-programmed reduction method and hypophosphite disproportionation method to investigate their naphthalene hydrogenation performance. The prepared catalysts were characterized by ICP-OES, X-ray diffraction, H2 temperature-programmed reduction, N2 adsorption-desorption method and transmission electron microscopy, etc. Results showed that Ni2P/SiO2 catalyst with pure Ni2P crystal phase could be successfully prepared by the temperature-programmed reduction method and hypophosphite disproportionation method. When the naphthalene hydrogenation reaction was performed at 340°C, 4 MPa, H2/oil volume ratio of 600, and a weight hourly space velocity (WHSV) of 20.8 h–1, Ni2P/SiO2 catalyst prepared by the temperature-programmed reduction method possessed superior hydrogenation activity. This result was ascribed to the advantages of temperature-programmed reduction method. It not only installed the higher number of Ni2P species (CO adsorption amount 21.6 μmol/g) over SiO2, but also obtained more weak acid sites on the catalyst surface, which promoted the adsorption of aromatic hydrocarbons and subsequently resulted in the higher hydrogenation activity. Furthermore, when the temperature-programmed reduction method was used to prepare Ni2P/SiO2 catalyst, the lower Ni/P molar ratio was more beneficial to enhance the naphthalene hydrogenation activity of the as-prepared catalyst.