The effect of support and synthesis method on the methanation activity of alumina-supported cobalt-ruthenium-lanthana catalysts

The effect of alumina support source as well as preparation method on the methanation activity of cobalt catalysts promoted with lanthanum and ruthenium was investigated. The catalysts were prepared by incipient wetness impregnation using either an acetone and ethanol mix (ratio 4:1 - non-aqueous) or using a dilute nitric acid solution (aqueous) on two commercial aluminas, Puralox SBA200 or Norton type SA6176 alumina. The catalysts were characterised by nitrogen adsorption/desorption, X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption of hydrogen and Fourier transform infrared spectroscopy. Both the support and synthesis method were found to influence the methanation activity with the non-aqueous plus Puralox combination giving the best performance. The activity differences could arise from modification of surface properties leading to variations in cobalt crystallite size and hence improved cobalt metal dispersion.