Sustainable Ammonia Production, Advances in Electrochemical, Photoelectrochemical, and Photocatalytic Technologies for Green Energy

Substantial advances have been made since the 1970s in reducing the environmental impacts of ammonia production. Renewable-driven electrochemical synthesis offers a promising pathway to decarbonize ammonia production. This review examines an integrated route in which hydrogen is generated photoelectrochemically under concentrated solar irradiation and subsequently used in electrochemical ammonia synthesis. Photoelectrochemical cells are fabricated by electrostatically depositing photosensitive particles onto cathodes to enhance light-driven hydrogen production. Hydrogen production rates and ammonia yield depend strongly on temperature and electrolyte composition. The synthesized hydrogen is fed into a molten salt electrochemical reactor that operates at atmospheric pressure and receives nitrogen from a dedicated supply. This combined solar–electrochemical approach can produce low-carbon ammonia with improved safety and reduced environmental impact, offering a scalable alternative to conventional processes.