Rethinking Haber–Bosch: Decentralized Green Ammonia Synthesis by Intensification and Electrification

Abstract This review article outlines the current state-of-the-art in small-scale ammonia (NH3) production via mild Haber-Bosch synthesis. Attention is devoted to addressing functional materials and process challenges and opportunities to intensify the thermo-catalytic synthesis of NH3 via its equilibrium-shifting separation, as well as to produce N2 and H2 via air separation and direct seawater electrolysis, respectively. This review also explores electrification as a major strategy at the catalyst, reactor, and process levels, emphasizing its potential to boost NH3 production rates even at atmospheric pressure, increase process flexibility, and support deep decarbonization. Finally, technological opportunities and research priorities are presented to advance the decentralized power-to-NH3 concept.