Hydrodeoxygenation of m-cresol over nickel and nickel phosphide based catalysts. Influence of the nature of the active phase and the support

Abstract

The present work studied the effect of two supports (SiO2 and tetragonal ZrO2) on the performance of metallic nickel and nickel phosphide catalysts for the hydrodeoxygenation (HDO) of m-cresol carried out at 340 °C under 4 MPa. All catalysts were characterized using several techniques (ICP, N2 adsorption-desorption, XRD, H2-TPR, NH3-TPD). The active phases (Ni(0) and Ni2P) were successively prepared at 450 °C under 4 MPa of H2, as observed by XRD. The activity and deoxygenation properties depended on the active phase (Ni vs Ni2P) and the support (SiO2 vs ZrO2). The order of HDO activity (mmol g−1 h−1) followed: Ni2P/ZrO2 (47.0) > Ni2P/SiO2 (28.3) >> Ni/ZrO2 (3.0) > Ni/SiO2 (1.1). The Ni2P phase was clearly much more active than metallic Ni. In addition, the use of zirconia as support enhanced the deoxygenation properties compared to silica, which can be attributed to the presence of oxophilic sites (Zr3+/Zr4+) favoring the adsorption of m-cresol.