Breathing air into water: dual-pathway H₂O₂ synthesis via aerating amphiphilic supramolecular films

Dual-pathway photosynthesis offers a sustainable method for producing hydrogen peroxide (H₂O₂) from air and water. The main efficiency-limiting step in existing photocatalytic systems is the simultaneous triphasic enrichment and activation of gaseous air and liquid water at the solid catalyst interface. In this work, utilizing amphiphilic molecular design and hierarchical self-assembly of asymmetric perylene diimide molecules (PDIOH), we developed an O₂-permeable 2D organic supramolecular film for dual-pathway H₂O₂ production. The resulting supramolecular films amplify the amphiphilic characteristics of PDIOH molecules, featuring Janus wettability on both sides, which anisotropically enrich and activate O₂ and H₂O molecules. Specifically, non-polar O₂ is enriched on the hydrophobic surface of the PDIOH films and then photoreduced to the polar O₂⁻ species, which subsequently detaches and enters the aqueous phase, mimicking the process of “breathing air into water”. Simply placing PDIOH films at the static air-water interface achieves a high H₂O₂ yield of 3046.15 μmol g⁻¹ h⁻¹ without the need for stirring, O₂ bubbling or small-molecule sacrificial agents. This setup allows for the continuous flow synthesis of H₂O₂ with a stable efflux concentration of at least ∼800 μM.