Amorphous Ni-B/γ-Al 2O 3 catalyst prepared in a modified drying approach and its excellent activity in benzene hydrogenation

Abstract

A two-step dying approach was proposed for the preparation of supported amorphous Ni-B/γ-Al 2O 3 catalyst. After wetness impregnation of NiCl 2 aqueous solution, the catalyst precursor was dried at 343 K first, followed by drying at 383 K before KBH 4 reduction (denoted as Ni-B/γ-Al 2O 3 (LT)). For comparison, the precursor was directly dried at 383 K and reduced by KBH 4 (denoted as Ni-B/γ-Al 2O 3 (HT)). Liquid phase hydrogenation of benzene to cyclohexane was employed as the probe reaction. While X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS) and turnover frequency (TOF) revealed no considerable electronic or structural difference between the active components of these two catalysts, scanning electron micrography (SEM), H 2 chemisorption and XPS intensity analysis demonstrated the higher dispersion of active component in the Ni-B/γ-Al 2O 3 catalyst prepared by the two-step drying approach, which can account for the superior catalytic performance of Ni-B/γ-Al 2O 3 (LT) to Ni-B/γ-Al 2O 3 (HT) in benzene hydrogenation.