Preparation of Ni/SiO₂–Al Catalyst and Its Performance for m-Cresol Hydrodeoxygenation

Abstract—A series of Ni/SiO₂–Al-x catalysts (x is the initial mass ratio of SiO₂ to Al(NO₃)₃) with different aluminum contents was prepared by impregnation method using nickel nitrate as the Ni source. The prepared Ni/SiO₂–Al-x catalysts were characterized by XRD, BET, TPR, TEM, XPS, NH₃-TPD, and Py-FTIR methods. Taking m-cresol as a model compound, the effects of aluminum content and reaction conditions on the HDO performance were investigated. Results showed that addition of appropriate amount of aluminum can generate acid sites and improve the metal Ni dispersion by increasing the surface area of catalyst. Furthermore, the selectivity to deoxygenated methyl-cyclohexane product over aluminum modified Ni/SiO₂–Al-x catalysts increased significantly as compared to that of Ni/SiO₂, which confirmed the importance of aluminum addition on the dehydration of 3-methyl-cyclohexanol to methyl-cyclohexane. Among the prepared Ni/SiO₂–Al-x catalysts, the Ni/SiO₂–Al-5 catalyst exhibits the best HDO performance. A 100% m-cresol conversion with the selectivity to MCH of 100% was achieved under the conditions of T = 250°C, p = 2 MPa, t = 75 min with catalyst (mg)/m-cresol solution = 2.