Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

Even after a century, ammonia (NH3) synthesis from nitrogen and hydrogen through Haber‐Bosch process is still energy intensive. Even with recently introduced second generation Ru based catalysts with superior performance over commercial Fe based catalysts, there is still place for upgrading with new approach using advanced materials in catalyst formulation. The alkali and alkaline metal promoted Ru supported carbon and metal oxide catalyst attracted attention at initial stage and extensively studied for NH3 synthesis in the 20th century. Until recently, advanced materials such as electrides, hydrides, nitrides, oxides and oxy‐hydrides‐nitrides studied as support and active component of catalyst fascinated much attention, with milder reaction conditions for NH3 synthesis. These materials with unique properties of reversible storage of electrons, hydrides, nitrides and oxygen vacancies enrich electron density on Ru catalyst and cleave N≡N bond with very low activation energy (