TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Properties: The vapor pressure of the primary and secondary ammonia storage materials are measured at the same reference temperature, and differs by more than factor of 2 or less than or equal to 2. The ammonia vapor pressure of the primary and secondary storage materials is less than 1 bar and less than 0.1 bar, respectively measured at room temperature. Preferred Materials: The storage materials are metal ammine complex of formula: Ma(NH3)nXz.M=cations chosen from lithium, sodium, potassium and cesium, alkaline earth metals such as magnesium, calcium and strontium, and/or transition metals such as vanadium, chromium, manganese, iron, cobalt, nickel, copper or zinc, or sodium-aluminum, potassium-aluminum, copper-cesium, potassium-iron (K2Fe) or potassium-zinc (K2Zn);X=anions chosen from fluoride, chloride, bromide, iodide, nitrate, thiocyanate, sulfate, molybdate, and phosphate ions;a=number of cations per salt molecule;z=number of anions per salt molecule;andn=coordination number of 2 to 12.The secondary ammonia storage material is preferably magnesium hexammine dichloride (Mg(NH3)6Cl2). The primary ammonia storage material is preferably octamine strontium dichloride (Sr(NH3)8Cl2) and/or octamine calcium dichloride (Ca(NH3)8Cl2). Preferred Method: The absorption of ammonia into storage container (4) is prevented by one-way valve or a closed valve (12) during release of ammonia from the ammonia storage container (1). The storage container (4) has heating unit, and is insulated. The primary and secondary ammonia storage materials are compacted to a unit with density of more than 75% of the theoretical maximum skeleton density of the saturated solid ammonia storage material. The desorbed ammonia is delivered to a catalyst (8) for a selective catalytic reduction of nitrogen oxide in an oxygen-containing exhaust gas from a combustion process or engine (7). Desorbed ammonia is delivered to a fuel cell directly or via a catalytic ammonia cracking reactor for cracking ammonia into hydrogen and nitrogen. The device further has units (5,10,11,13) for controlling and introducing gaseous ammonia from the storage container (4) into an exhaust line (9) before nitrogen oxide reduction catalyst (8) and unit (12) for connecting the containers (1,4) and having valve (12).