PhotocatalyticAmmonia Synthesis: Catalysts Design Strategies, Progress, and Prospects

Ammonia (NH 3 ), recognized as a prospective green energy carrier due to its high hydrogen density and ease of transport, has garnered significant attention. However, the conventional Haber–Bosch (H–B) process for ammonia synthesis necessitates high-temperature and high-pressure conditions, accompanied by substantial carbon dioxide emissions. Consequently, the development of novel green ammonia synthesis technologies has become a focal point of research. Photocatalytic ammonia synthesis, leveraging solar energy as the driving force, converts nitrogen to ammonia under ambient conditions, offering advantages such as low energy consumption and environmental friendliness.

This review summarizes recent advancements in photocatalytic ammonia synthesis, emphasizing nitrogen activation mechanisms, photocatalytic reaction pathways, and the design and optimization strategies for various photocatalysts. Through a detailed analysis of biomimetic catalysts, Ti-based materials, Bi-based materials, metal–organic frameworks (MOFs) materials, graphitic carbon nitride (g-C 3 N 4 ) materials, and MXene materials, their applications and limitations in photocatalytic ammonia synthesis are discussed. Furthermore, this paper synthesizes photocatalyst design strategies, including morphology control, vacancy engineering, and bandgap engineering, aiming to provide theoretical support and practical guidance for the design of future novel photocatalysts.