The PS-3-INS and PS-3-INS-R catalysts are designed for the synthesis of ammonia from hydrogen and nitrogen.

The PS-3-INS catalyst contains Fe₂O₃ and FeO as main components, and K₂O, Al₂O₃, MgO, CaO, as promoters. An active component of the catalyst after its reduction is iron. Alumina is structural promoter which provides the catalyst with a good thermal stability and a high mechanical strength. Calcium oxide and magnesium oxide increase resistances of the catalyst to overheating and to poisoning by sulfur and chlorine compounds. Potassium oxide is an promoter which enhances activity of the catalyst. The PS-3-INS-R catalyst is prereduced form of the PS-3-INS catalyst.