Reducing the Ni2P Particle Size Through the Silicon–Aluminium Coordination for Efficient Hydrogenation Saturation of Naphthalene

Though alumina and silica are well-known and widely used supports, they have notable drawbacks, such as the formation of the AlPO4 phase and inadequate metal–support interactions with nickel phosphide. This study investigates the synergistic effects of silica and alumina on the physicochemical properties and catalytic performance of nickel phosphide catalysts. Catalysts supported by alumina (Al2O3), silica (SiO2), and a composite silica-alumina (ASA) have been simultaneously prepared using a straightforward isopyknic co-impregnation method in order to eliminate the influence of preparation conditions. The results indicated that Ni2P/SiO2 exhibited poor dispersion, while Ni2P/Al2O3 showed a larger particle size along with the formation of the AlPO4 phase. The coordination between silicon and aluminum facilitated the reduction of nickel phosphate to nickel phosphide (Ni2P) and inhibited the formation of AlPO4. Ni2P/ASA demonstrated an improved dispersion and smaller particle size. Therefore, a comparative study of the Ni2P/SiO2, Ni2P/ASA, and Ni2P/Al2O3 performance revealed the superior catalytic efficacy of the SiO2–Al2O3 supported Ni2P in the naphthalene hydrogenation.