Advanced cold plasma-assisted technology for green and sustainable ammonia synthesis

Ammonia (NH₃) is the most crucial industrial chemical feedstock for producing fertilizers and is a promising future hydrogen carrier. Recent research has spurred for the development of alternative green and sustainable ammonia production technologies. Cold plasma technology provides a clean, sustainable method for nitrogen (N₂) conversion into active species for ammonia synthesis. Synergistic action of cold plasma and catalyst has significantly improved the current production rate and selectivity. Present energy consumption (2.1 MJ mol N⁻¹) for N₂ fixation via plasma-assisted technology is still higher than the commercial process (0.7 MJ mol N⁻¹), while a further improvement would be game-changing. In this review, we explain the takeover by plasma-assisted technology and its potential for green and sustainable ammonia production. We briefly present that the major challenge in nitrogen fixation of N₂ to NO_x as an intermediate pathway, can be addressed by plasma technology via NO_x transformation into targeted NH₃ product. We discussed the emerging plasma and catalysis synergism, mechanisms involved and highlighted current research development in selective ammonia generation. Finally, we outlined the ways to achieve cleaner and sustainable ammonia production and challenges in future work.