NICKEL-IRON CATALYSTS PREPARED BY HOMOGENEOUS DEPOSITION-PRECIPITATION OF CYANIDE COMPLEXES ON A TITANIA SUPPORT

Nickel-iron catalysts have been prepared by homogeneous deposition-pre cipitation of complex nickel-iron cyanides on a titania support. The n ickel-iron alloys obtained after calcination and reduction of the cyan ide precursors were characterized by Mossbauer spectroscopy, high-temp erature X-ray diffraction, and magnetic measurements. Fischer-Tropsch experiments show remarkable results. Catalysts prepared from K3Fe(CN)( 6) and Na2Fe(CN)(5)NO cyanide precursors exhibit a high activity and s electivity, whereas catalysts prepared from K4Fe(CN)(6) do not show an y activity. This lack of activity is caused by the presence of potassi um in catalysts prepared from K4Fe(CN)(6). Potassium or iron titanate inhibits the adsorption of CO on the nickel-iron surface. Deactivation of active nickel-iron catalysts was caused by the deposition of inact ive carbon during Fischer-Tropsch synthesis.