Abstract: A transition metal catalyst suitable for use in the synthesis of ammonia is produced by doping an activated carbon support material with a solution of an alkaline earth metal compound, a solution of a compound of a transition metal from Group VIII and a solution of an alkali metal compound. Each doping is performed separately; the product of each step is baked to obtain a catalyst having a black and lustrous surface. The doping and the baking operations are preferably conducted under vacuum.The catalyst is preferably prepared with barium as the alkaline earth metal, ruthenium as the transition metal and potassium as the alkali metal. The activated carbon support material can additionally be doped with a solution of a compound of a lanthanide metal and/or a solution of a compound of a Group IIIA metal.The present family of catalysts provides good ammonia yields in the fixation of nitrogen at temperatures as low as 375.degree. C. and at pressures ranging from 27 - 67 atmospheres.