LAUSR

Harnessing solar energy to convert molecular N2 into nitrogen‐rich chemicals (e.g., ammonia) provides a potential pathway for the manufacture of “solar fertilizers”. However, the solar‐to‐ammonia (STA) efficiency of most solar fertilizer systems developed to date is less than 0.1%. Herein, an outstanding STA efficiency of ≈0.3% using a metallic molybdenum trioxide (metallic MoO3‐x) photocatalyst under simulated‐solar irradiation is reported, with localized surface plasmon resonance phenomena in the metallic MoO3‐x photocatalyst enhancing both light utilization and N2 activation. The potential scalability of the photocatalytic technology is demonstrated in a 1 m2 panel reactor system, with a high STA efficiency and good stability demonstrated over 6 days of outdoor testing, yielding a solid (NH4)2SO4 product for easy collection. The as‐designed square‐meter outdoor reaction system facilitates the integration of solar fertilizer technology with existing agricultural infrastructure.