Solar‐Driven Conversion of Nitrogen and Water to Solid Fertilizer in an Outdoor 1 m2 Panel Reactor

Abstract Harnessing solar energy to convert molecular N 2 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 MoO 3‐x ) photocatalyst under simulated‐solar irradiation is reported, with localized surface plasmon resonance phenomena in the metallic MoO 3‐x photocatalyst enhancing both light utilization and N 2 activation. The potential scalability of the photocatalytic technology is demonstrated in a 1 m 2 panel reactor system, with a high STA efficiency and good stability demonstrated over 6 days of outdoor testing, yielding a solid (NH 4 ) 2 SO 4 product for easy collection. The as‐designed square‐meter outdoor reaction system facilitates the integration of solar fertilizer technology with existing agricultural infrastructure.