Preparation, characterisation and catalytic behaviour of cobalt–niobia catalysts

Abstract

Cobalt–niobia catalysts were prepared using the colloidal sol–gel technique. Niobium chloride or niobia oxide were used as precursor. The differences between the procedures used are due to the methods of preparation of the colloidal suspensions and gelification. The catalysts were characterised using adsorption and desorption curves of Kr and N 2 at 77 K, H 2-Chemisorption, XRD, FT-IR, XPS and electron microscopy investigations. Preparation of these catalysts without experimental precautions led to a very inhomogeneous structural and textural material. In contrast, the colloidal sol–gel technique controls both the structure of the niobia oxide and the tailoring of cobalt. A strong metal support interaction effect (SMSI) was present irrespective of the sample preparation variant. Although the rate of butane hydrogenolysis was low for all catalysts, a correlation between TOF and the catalyst crystallite size was found. Selectivity to methane, ethane, propane or to isomerization also depends on the catalyst crystallite size.