TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Method: In the method for producing hydrogen, comprising a reaction and formation step and a reaction and acceleration step, the metallic material is either metal, metallic alloys, or metal scrap, the acidic material is organic acid or non-organic acid, and the electrolyte solution is of electrical conductivity or is an acidic solution. The organic acid is acetic acid, formic acid or citric acid, and the non-organic acid is hydrochloric acid, sulfuric acid or nitric acid. The method further comprises an extended treatment step performed by drying an electrolyte solution of metal ions produced after hydrogen production reaction, and treating the electrolyte solution of metal ions with absolute alcohol or tetrahydrofuran (THF) where the electrolyte solution of metal ions able to be reapplied as an electrode material of rechargeable batteries. The metallic material is further combined with a catalyst, the combined metallic material and the catalyst chemically contacted with the acidic electrolyte solution so as to generate the chemical reaction and an electrochemical reaction for accelerating the hydrogen production rate. The method further comprises an extended treatment step performed by reducing an electrolyte solution of metal ions produced after hydrogen production reaction by way of electrolysis to metal, the metal reused as material for producing hydrogen with the method or as an electrode material of rechargeable batteries. Producing hydrogen comprises a reaction and formation step and a reaction and acceleration step, where the reaction and formation step is performed by (a) providing dissimilar metals; (b) cleaning the dissimilar metals and then combining the dissimilar metals for being used as reaction objects for producing hydrogen; and (c) immersing the combined dissimilar metals in either an electrolyte solution or water to result in an electrochemical reaction through reduction potential difference between the dissimilar metals thus to produce hydrogen and by-products thereof; and the reaction and acceleration step performed to accelerate hydrogen production rate through an chemical reaction by adding an acidic material while performing the reaction and formation step. One of the dissimilar metals of lower reduction potential is defined as a positive electrode as an anode metal, the anode metal selected from a metal scrap product made of magnesium alloy or aluminum alloy, while the other one of the dissimilar metals of higher reduction potential is defined as a negative electrode as a cathode metal, the cathode metal is stainless steel or platinum. The dissimilar metals are combined with steps of: (a) smashing the anode metal; (b) melting the smashed anode metal in a furnace; (c) spraying the molten anode metal on the cathode metal; and (d) rolling up the cathode metal attached with the anode metal to be tube-shaped, or directly conveying the cathode metal attached with conveyor belts, into a hydrogen production reactor. The dissimilar metals are combined with steps of: (a) smashing the anode metal and the cathode metal to be grain-shaped or irregular shape; and (b) contacting the anode metal with the cathode metal in a hydrogen production reactor. The acidic material is organic acid or non-organic acid, where the organic acid is acetic acid, formic acid or citric acid, and the non-organic acid is hydrochloric acid, sulfuric acid or nitric acid. The method further comprises an extended treatment step performed by drying an electrolyte solution of metal ions produced after hydrogen production reaction, and treating the electrolyte solution of metal ions with absolute alcohol or THF where the electrolyte solution of metal ions able to be reapplied as an electrode material of rechargeable batteries. The method further comprises an extended treatment step performed by reducing an electrolyte solution of metal ions produced after hydrogen production reaction by way of electrolysis to metal, the metal reused as material for producing hydrogen with the method or as an electrode material of rechargeable batteries. Producing hydrogen comprises (a) providing a reaction object made of a metallic material; (b) cleaning the reaction object; and (c) having the cleaned reaction object chemically contacted with an electrolyte solution so as to generate a chemical reaction thus to produce hydrogen and by-products thereof. The method further comprises an extended treatment step performed by drying an electrolyte solution of metal ions produced after hydrogen production reaction, and treating the electrolyte solution of metal ions with absolute alcohol or THF where the electrolyte solution of metal ions able to be reapplied as an electrode material of rechargeable batteries. The method further comprises an extended treatment step performed by reducing an electrolyte solution of metal ions produced after hydrogen production reaction by way of electrolysis to metal, the metal reused as material for producing hydrogen with the method or as an electrode material of rechargeable batteries.