Materials Used to Produce Hydrogen

Hydrogen is the simplest and most widely distributed element in nature. It constitutes about 1 percent of the earth's crust, including water and air. Hydrogen is mainly produced by a chemical process from hydrocarbon fossil fuels. Hydrogen can also be produced by extraction from water through biological production in an algal bio-reactor, or using chemicals (i.e. chemical reduction), electricity (i.e. electrolysis), and heat (i.e. thermolysis). However, these methods are not widely used when it comes to the bulk production of hydrogen gas.

From Hydrocarbons

• The method of production of hydrogen from hydrocarbon compounds includes combining a base with a hydrocarbon compound, which follows a reaction liberating hydrogen gas as the main product. The reaction can be accelerated by a catalyst and/or water to the reaction mixture. Hydrogen gas thus generated is approximately 80 per cent pure. The hydrocarbon conversion also produces harmful carbon dioxide gas as a byproduct. This carbon oxide can be separated and disposed of properly.

By Electrolysis

• Hydrogen gas is also obtained from hydrogen ions by electrolysis of water containing a little acid or alkali. One method involves electrolysis of a warm, saturated solution of barium hydroxide solution with nickel electrodes. Hydrogen gas produced by the electrolysis of water is very pure. About 18 percent of the world production of hydrogen gas is obtained by this electrochemical method. This process can be economically feasible where electricity is cheap. In a preferred embodiment, renewable energy sources such as wind turbines, photovoltaic cells and hydropower may be used in the production of hydrogen gas that is more economic and without pollution.

Preparation of Hydrogen by the Action of Metals

• Hydrogen is liberated from aqueous solutions of acids or water by many metals, i.e., lithium, sodium and potassium. which follow hydrogen in the electrochemical series (i.e. in electrochemical series metals are arranged in order of increasing ease of reduction, or ability to lose electrons). Thus all alkali metals react with violence to water, and explosively to acid solutions even at room temperature.

  On a laboratory scale, the usual method of preparing hydrogen is based on the action of dilute sulfuric acid on metallic zinc.

From Water Gas

• Water gas is evolved when steam is passed over red-hot carbon. Water gas in a mixture with steam in the presence of an iron catalyst or cobalt oxide as a catalyst promoter at 400 degree C transforms into a mixture of carbon dioxide and hydrogen gas. From this mixture, hydrogen gas is extracted by removing carbon dioxide through absorption in water under 20 atmosphere pressures.

By the Action of Steam on Iron

• On one large industrial scale, hydrogen gas is produced by the reaction between steam and iron. Steam is passed over red-hot iron. The iron is regenerated by heating in water gas or any other reducing gas and used again.