What is the role of promoters in Haber's process?

Haber’s process is a specialized industrial method used to synthesize ammonia (NH3) from nitrogen (N2) and hydrogen (H2) gases. Finely divided iron (Fe) is used as a catalyst to increase the reaction rate. Promoters potassium hydroxide (KOH) and aluminum oxide (Al2O3) are also added to increase the effectiveness of the iron catalyst. 

The two promoters – KOH and Al2O3 – serve a vital role in Haber’s process. They prevent the aggregation of iron particles, thereby increasing the surface area of the iron catalyst, making more space available for the reactants (N2 and H2) to bind to. This improves the active characteristics of the catalyst and enhances its overall efficiency in the reaction, resulting in a higher yield of ammonia.