Mechanistic Insights and Catalyst Exploration for Photothermal Catalytic Ammonia Synthesis

Ammonia (NH₃) serves as a key component in the majority of fertilizers, chemicals, and pharmaceuticals. The conventional Haber-Bosch process is highly energy-intensive, accounting for 2% of global energy consumption annually and contributing significantly to greenhouse gas emissions. In recent years, photothermal catalysis, driven by light energy, has emerged as a highly promising approach to synthesizing ammonia under green and mild conditions. By leveraging the synergy between the photochemical and thermochemical effects of sunlight, this method drives chemical reactions efficiently, which offers significant potential to enhance reaction rates and tune selectivity. This review begins with a brief introduction to the principles and limitations of conventional thermal catalysis, highlighting the advantages and mechanisms of photothermal ammonia synthesis. It then categorizes different types of photothermal ammonia synthesis based on their primary reaction pathways. Furthermore, design strategies for photothermal catalysts and methods to improve catalytic activity are discussed. Finally, perspectives and forward-looking suggestions are provided for the future development of photothermal ammonia synthesis.