Pyrene-Based Covalent Organic Frameworks for Photocatalytic Hydrogen Peroxide Production

Four highly porous covalent organic frameworks (COFs) containing pyrene units were prepared and explored for photocatalytic H₂ O₂ production. The experimental studies are complemented by density functional theory calculations, proving that the pyrene unit is more active for H₂ O₂ production than the bipyridine and (diarylamino)benzene units reported previously. H₂ O₂ decomposition experiments verified that the distribution of pyrene units over a large surface area of COFs plays an important role in catalytic performance. The Py-Py-COF though contains more pyrene units than other COFs which induces a high H₂ O₂ decomposition due to a dense concentration of pyrene in close proximity over a limited surface area. Therefore, a two-phase reaction system (water-benzyl alcohol) was employed to inhibit H₂ O₂ decomposition. This is the first report on applying pyrene-based COFs in a two-phase system for photocatalytic H₂ O₂ generation.