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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.

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An ammonium tetrathiomolybdate (ATTM) catalyst precursor is synthesized and then thermally decomposed at different temperatures in N 2 or H 2 atmosphere. Characterization of the resulting compounds by powder X-ray diffraction (XRD) and surface area analysis indicates the formation of MoS 2 -2H with a surface area of 5-9 m 2 /g. When ATTM is treated with cetyltrimethylammonium chloride and then decomposed in N 2 at 723 K, the resulting material has a surface area nearing 200 m 2 /g. If treatment also includes hydrazine, the surface area of the resulting MoS 2 -2H reaches 215 m 2 /g. Analysis by XRD and electron microscopy shows a noticeable dispersion in the layers of the resulting MoS 2 . The catalytic activity of the materials is tested in a batch reactor for cyclohexene hydrogenation, where the highest activity sulfides are those obtained by thermal decomposition of the chemically treated precursors in N 2 .