Hydrogenation of cyclohexanone on nickel-tungsten sulfide catalysts Original Research Article

Unsupported Ni-W sulfide catalysts were tested for cyclohexanone hydrogenation under atmospheric pressure conditions and showed a high selectivity towards cyclohexene. They were prepared employing ammonium thiotungstate complexes and nickel nitrate as metal-sulfide precursors. The data of catalytic activity show a synergetic effect as a function of stoichiometric composition, R=Ni/(Ni+W). A maximum synergetic effect occurred at R=0.7. The texture and surface composition characterization of the catalysts were carried out by BET surface area measurements, AES and XPS. The surface of catalysts was found to be nickel deficient, compared to the nominal values, as determined by AES and XPS. The electronic state of Ni changed as the catalyst stoichiometry varied, but the electronic state of W did not change.