Characterization and catalytic properties of several potassium-doped iron-nickel catalysts

Studies of the chemical preparation, BET surface areas. X-ray diffraction, X-ray photoelectron spectra, and catalytic activities of several potassium-doped iron-nickel catalysts were carried out for the catalytic hydrogenation of 1,6-hexanedinitrile, in a continuous process at 1 atm pressure, 443 K, and in the absence of ammonia. Surface areas decrease with NiO reduction in the absence of potassium, and increase in the presence of doping amounts of potassium. XRD measurements show Fe3O4, α-Fe and NiO phases, but generally no metallic nickel is detected due to crystallite sizes <50Å. X-ray photoelectron spectroscopy detects higher concentrations of potassium and reduced nickel on the surface than in the bulk. A potassium inhibitor character upon the reduction of NiO and potassium and nickel promoting effects upon the reduction of Fe3O4 are observed. 100% selectivities with respect to 6-aminohexanenitrile are obtained at 55% conversions for catalysts with potassium contents of 10.5 × 10−4 g K2O/g Ni.