Synthesis and characterization of nickel sulfide catalysts

Abstract

Nickel sulfide catalysts obtained. by homogeneous precipitation were prepared by varying the homogenization time and the sulfiding temperature. Structural characterization studies by transmission electron microscopy and x-ray diffraction showed the formation of various metastable crystalline phases at low temperatures of sulfiding (Ni3S2, Ni3S4, Ni7S6, Ni9S8, NiS2, NiS1.03, NiS), depending on the preparation conditions. NiS millerite appears to be the main phase for samples obtained after 4 h homogenization, changing to NiS1.03 phase after 36 h. Catalytic tests of these samples for cyclohexanone hydrogenation showed that the intrinsic activity is higher for the NiS1.03 phase. (C) 1998 American Vacuum Society. [S0734-2101(98)01306-2].