NOVELTY - Water is decomposed at 10-60degrees C in a reaction system which contain compositions (A-C), to obtain pure hydrogen or deuterium. The composition (A) is abundant metal. The composition (B) is water, alcohol or heavy water. The composition (C) is a catalyzer which is an oxidated metallic hydronium salt containing copper, iron, tin, chrome, molybdenum, titanium, vanadium, columbium, nickel, cobalt, zirconium, manganese, aluminum, zinc or magnesium.    USE - Manufacture of pure hydrogen or deuterium used in fuel battery used for vehicles.    DETAILED DESCRIPTION - Water is decomposed at 10-60degrees C in a reaction system which contain compositions (A-C), to obtain pure hydrogen or deuterium. The composition (A) is abundant metal. The composition (B) is water, alcohol (R(OH)n) or heavy water. The composition (C) is a catalyzer which is an oxidated metallic hydronium salt containing copper, iron, tin, chrome, molybdenum, titanium, vanadium, columbium, nickel, cobalt, zirconium, manganese, aluminum, zinc or magnesium. The mol rate of the composition (B) and composition (A) is 10-1000:1. The composited rate between the composition (C and A) depends on the number of atoms on the surface of the metal. The rate between the mol of the catalyzer in the initial reaction and number of atoms on a surface of the metal in the initial reaction, is 1 or less. The abundant metal is an alloy or mixture of alloy containing metal chosen from aluminum, iron, chrome, manganese, vanadium, tin, titanium, zinc, columbium, nickel, cobalt or magnesium. The alcohol is chosen from carbinol, ethanol, propyl alcohol, isopropyl alcohol, 1-butanol, butane diol, glycol, glycerol or pentaerythritol. The negative hydronium of catalyzer is sulfuric acid, hydrochloric acid, hydrobromic acid, hydrofluoric acid, chlorate, phosphate, sulfonic acid, oxalic acid and nitric acid. The compositions (A-C) are chosen from aluminum/water/trivalent aluminum ion, iron/water/ferric ion, chromium/water/trivalent chromium ion, manganese/water/divalent manganese ion, divalent vanadium ion/water/trivalent vanadium ion, divalent manganese ion/water/trivalent manganese ion, iron/water/ferrous ion, vanadium/water/ trivalent vanadium ion, trivalent titanium ion/water/tetravalent titanium ion, titanium/water/divalent titanium ion, divalent titanium ion/water/trivalent titanium ion, titanium/water/tetravalent titanium ion, iron/water/trivalent aluminum ion, aluminum/water/ferric ion, aluminum/water/tetravalent titanium ion, aluminum/water/trivalent chromium ion, aluminum/water/tetravalent manganese ion, aluminum/water/ferrous ion, chromium/water/trivalent aluminum ion, iron/water/trivalent chromium ion, aluminum/heavy water/ferric ion, iron/heavy water/trivalent aluminum ion, aluminum/heavy water/trivalent chromium ion and aluminum/heavy water/tetravalent manganese ion.