Graphitised carbon as support for Ru/C ammonia synthesis catalyst

In the present work, we compared the catalytic activity and mainly the stability under the usual ammonia synthesis conditions, of some carbon supports, differing as for their nature, purity and temperature of pretreatment. The effect of catalyst composition (metal and promoters loading) on stability was also investigated. XRD and N2 adsorption/desorption analysis helped in elucidating the effect of carbon treatment. It was found that only after the support has been heated at least at 1900 °C the stability of the tri-promoted catalyst becomes fully satisfactory and virtually independent of Ru loading. For practical purposes such high temperature treatment must be compatible with the preservation of a sufficiently high surface area.