Catalysis
the process of facilitating chemical reactions by the introduction of agents which do not themselves enter into the reactions. It was first discovered by Jacob Berzelius and is now employed widely in various industries, as in some processes of nitrogen fixation and in the manufacture of sulphuric acid. In the latter manufacture, platinum is used as a catalyzer to facilitate the combining of oxygen and sulphur dioxide. In the Haber process of nitrogen fixation, several catalyzers have been employed for the purpose of causing nitrogen and hydrogen to unite in ammonia.