How is ammonia made from nitrogen and hydrogen in the Haber-Bosch process?

The Haber-Bosch process is an industrial method used to synthesize ammonia by directly combining nitrogen from the air with hydrogen.12

To overcome the inert nature of nitrogen, the reaction is conducted under specific conditions:

• High Pressure: The process utilizes extremely high pressures, typically ranging from 200 to 400 atmospheres, to favor the formation of ammonia.12
• Temperature: The reaction occurs at moderately high temperatures, generally between 400° and 650° C (750° to 1200° F).1
• Catalyst: An iron-based catalyst is employed to enable the reaction to proceed at a practical rate and temperature.13

To ensure a high yield, ammonia is removed from the reaction batch as soon as it is formed, which maintains an equilibrium that favors continued product formation. The hydrogen required for this process is typically obtained by decomposing water or from fossil fuels. This method remains the most economical approach for nitrogen fixation in the global chemical industry.12