Self-floating COF-based Janus film: A robust triphase interface boosting charge separation for efficient H2O2 photosynthesis

H 2 O 2 photosynthesis, as a gas-liquid-solid reaction, faces two giant challenges, i.e., charge recombination and sluggish oxygen transport. For improving efficiency, it is a feasible strategy to construct a robust triphase interface with optimized charge kinetics. Herein, we constructed a self-floating covalent-organic framework (COF)-based film with Janus heterostructure, i.e., COF-[NH 2 -GO]. In overall H 2 O 2 photosynthesis, COF-[NH 2 -GO] exhibited the highest yield among COF film and powder, signifying improved separation and transfer of photogenerated carriers. The photocatalytic triphase system achieved 5,306.6 μmol·m −2 ·h −1 H 2 O 2 yield, higher than that of diphase counterpart, ascribed to the promoted O 2 delivery. It was demonstrated that excellent photocatalytic performance was attributed to the improved charge kinetics and mass transfer. A prototypical film-based device was designed for photosynthesis and collection of H 2 O 2 , which exhibited bactericidal activity against Escherichia coli . More importantly, this strategy could be extended to other COFs and functional nanomaterials. This work provides new insights for challenging triphase photocatalysis.