Heterogeneous catalysis is a type of catalysis where the catalyst and the reactants are in different phases, usually solid and gas, respectively. In the Haber process, nitrogen N2 and hydrogen H2 gases are combined to synthesize ammonia NH3 under high pressure and temperature. The catalyst used in this process is typically iron with small amounts of other elements such as potassium, aluminum, or silicon as promoters.The mechanism of heterogeneous catalysis in the Haber process can be described in the following steps:1. Adsorption: Nitrogen and hydrogen molecules are adsorbed onto the surface of the solid catalyst iron . The adsorption process weakens the strong triple bond in nitrogen molecules and the bond between hydrogen atoms, making them more reactive.2. Dissociation: The nitrogen and hydrogen molecules dissociate into individual atoms on the catalyst surface. This step is crucial as it breaks the strong bonds in the reactant molecules, allowing them to form new bonds with each other.3. Reaction: The nitrogen and hydrogen atoms on the catalyst surface react with each other to form ammonia molecules NH3 . This step involves the formation of new bonds between nitrogen and hydrogen atoms.4. Desorption: The ammonia molecules formed in the previous step are released from the catalyst surface into the gas phase. This step completes the catalytic cycle, and the catalyst is now free to adsorb more reactant molecules and continue the process.The role of the catalyst in the Haber process is to lower the activation energy required for the reaction to occur, thus increasing the reaction rate. The catalyst provides an alternative reaction pathway with a lower activation energy, allowing the reaction to proceed at a faster rate and under milder conditions than would be possible without the catalyst. Additionally, the catalyst remains unchanged at the end of the reaction and can be used repeatedly, making the process more efficient and cost-effective.In summary, the mechanism of heterogeneous catalysis in the Haber process involves adsorption, dissociation, reaction, and desorption steps on the surface of the solid catalyst. The catalyst plays a crucial role in lowering the activation energy and increasing the reaction rate, enabling the efficient synthesis of ammonia from nitrogen and hydrogen gases.