The Effect of Thermal Treatment under Different Atmospheric Conditions on the Catalytic Performance of Nickel Supported on Porous Silica in the Gas-Phase Hydrogenation of Acetonitrile

Abstract

A series of mesoporous silica-supported nickel catalysts (2.2 wt% Ni) were prepared by impregnation employing the incipient wetness technique using Ni(II) formate as the impregnation salt. Three different atmospheric conditions were employed during the thermal treatment: air, He and H₂. The catalysts were characterised by chemical analysis, XRD, N₂ adsorption at −196°C, H₂-TPR, H₂-TPD and XPS. A direct relationship was found between catalytic activity in the gas-phase hydrogenation of acetonitrile and the Ni 2p_3/2 binding energy assigned to the Ni⁰ atoms of the reduced catalysts, where the catalytic activity decreased with increasing binding energy. The best catalyst obtained was that prepared by thermal decomposition in air and subsequent reduction in a hydrogen atmosphere; this catalyst displayed a high metallic surface and a low value for the Ni 2p_3/2 binding energy of Ni⁰.