Performance of Pt-doped Ni/NiAlO_x catalysts for phenanthrene hydrogenation saturation

Limited by the steric hindrance, hydrogenation of the final unsaturated ring in polycyclic aromatic hydrocarbons remains a challenge. In this work, a series of Pt-Ni/NiAlO_x catalysts were synthesized by impregnation method to enhance the adsorption of aromatics, and phenanthrene was served as the model compound. The effects of Pt content on the structure and saturation performance of Pt-Ni/NiAlO_x catalysts were systematically investigated. When the saturation reaction was performed at 300 ℃, 5 MPa and a weight hourly space velocity of 52 h⁻¹, the selectivity of perhydrophenanthrene could be enhanced from 40% over Ni/NiAlO_x catalysts to 67% over 0.5Pt-Ni/NiAlO_x catalysts with 0.5% Pt loading. Meanwhile, the obvious reaction rate and turnover frequency were also improved from 1.53×10⁻³ mol·kg⁻¹·s⁻¹ and 14.64×10⁻³ s⁻¹ to 1.81×10⁻³ mol·kg⁻¹·s⁻¹ and 22.16×10⁻³ s⁻¹ respectively. This is related to the modified stability of metallic electron-deficient structure of Ni by Pt introduction in phenanthrene hydrogenation, which can promote the adsorption of aromatic hydrocarbons as well as the hydrogenation activity.