Catalytic Reactor-Utilized Ammonia Adsorption, Absorption, and Storage Materials: Mechanism, Nanostructure, and

As the world's technological development shifts toward a sustainable energy future by harnessing renewable energy sources, ammonia is gaining recognition as a complementary green vector to hydrogen. This energy-dense carbon-neutral fuel is capable of overcoming hydrogen's limitations in terms of storage, distribution, and infrastructure deployment. The biggest challenge to the global use of ammonia as an energy storage medium remains more efficient, readily deployable production of ammonia from abundant, yet intermittent, sources. Green decentralized ammonia production, which refers to the small-scale, localized ammonia production utilizing environmentally sustainable methods, offers a promising approach to overcoming the challenges of traditional ammonia synthesis. The process aims to minimize carbon emissions, increase energy efficiency, and improve accessibility to ammonia in remote regions. Ammonia separation using sorbent materials holds significant potential in green ammonia production, providing a viable alternative to conventional condensation-based separation methods, with particular benefits in improving energy efficiency. This perspective summarizes recent developments in the field of ammonia separation, focusing on newly developed sorbents for the integrated ammonia synthesis-separation process, particularly metal halides that could potentially replace a conventional ammonia condenser. The challenges and potential solutions are also discussed. Moreover, this perspective outlines the mechanism of ammonia absorption into metal halides with its kinetics and thermodynamics. The use of computational methods for the development of new materials is also described, thereby laying the foundations of green ammonia technology.