Light-powered ambient-pressure ammonia synthesis using a plasmonic semiconducting catalyst

Ammonia plays a critical role in our society, not only as the source for fertilizers and other essential chemicals, but also as a promising hydrogen carrier due to its high energy density and ease of storage and transportation. However, the conventional Haber–Bosch process is energy-intensive and costly. Developing a more energy efficient route for ammonia production is currently a holy grail in scientific society. This study reports a plasmonic semiconductor catalyst, molybdenum oxynitride (Mo₂N/MoO_2−x) nanosheet, that enables the ambient-pressure NH₃ synthesis under light illumination. This catalyst achieves a remarkable NH₃ production rate of 2338 µmol·g⁻¹·h⁻¹ at 400 °C and 857 µmol·g⁻¹·h⁻¹ at room temperature. Notably, we present the evidence for the coexistence of both nonthermal and photothermal effects, distinguishing this system from photothermally driven routes. This work demonstrates a viable pathway for NH₃ production with low monetary and energetic investments and potential for distributed NH₃ synthesis utilizing only water, air, and sunlight.