Sunlight‐Driven Hydrogen Peroxide Production from Water and Molecular Oxygen by Metal‐Free Photocatalysts

Design of green, safe, and sustainable process for the synthesis of hydrogen peroxide (H 2 O 2 ) is a very important subject. Early reported processes, however, require hydrogen (H 2 ) and palladium‐based catalysts. Herein we propose a photocatalytic process for H 2 O 2 synthesis driven by metal‐free catalysts with earth‐abundant water and molecular oxygen (O 2 ) as resources under sunlight irradiation ( λ >400 nm). We use graphitic carbon nitride (g‐C 3 N 4 ) containing electron‐deficient aromatic diimide units as catalysts. Incorporating the diimide units positively shifts the valence‐band potential of the catalysts, while maintaining sufficient conduction‐band potential for O 2 reduction. Visible light irradiation of the catalysts in pure water with O 2 successfully produces H 2 O 2 by oxidation of water by the photoformed valence‐band holes and selective two‐electron reduction of O 2 by the conduction band electrons.