Covalent Organic Frameworks as Efficient Photocatalysts for Sustainable Ammonia Production

Ammonia is one of the most important industrial products. The Haber-Bosch process has enabled large-scale ammonia production but also results in substantial carbon emissions. Amid growing environmental concerns, there is an urgent need to transform this highly energy-intensive process and develop ammonia synthesis technologies under mild conditions. Covalent organic frameworks (COFs), as one of the most prominent emerging materials in recent years, have demonstrated exceptional application potential and advantages in various fields such as photocatalysis and electrocatalysis. The modular structural design of COFs allows for tunable band gaps according to practical requirements, their permanent porosity endows the materials with excellent adsorption capabilities for reactants, and the abundant heteroatoms provide numerous reactive sites. Currently, COFs-based catalysts have achieved high performance in various photocatalytic applications, and sustainable ammonia synthesis is highly likely to become the next research focus. This review summarizes the fundamental principles of photocatalytic ammonia synthesis, methods for ammonia detection, and the research progress in COFs-based materials for ammonia synthesis. Finally, it analyzes and discusses the future challenges and prospects of this emerging field of sustainable ammonia synthesis using COFs.