Visible-light responsive PDI/rGO composite film for the photothermal catalytic degradation of antibiotic wastewater and interfacial water evaporation

A visible-light responsive self-assembled perylenetetracarboxylic diimide (PDI)/reduced graphene oxide (rGO) composite film was obtained and showed excellent photocatalytic performance and efficient interfacial steam generation. The degree of π-π interactions between Perylenetetracarboxylic diimide supramolecular nanofibers (nano-PDI) and rGO regulated the energy band structure and redox potential of the composite film to produce h+ and O2− active species. The photothermal conversion of the composite film under visible light irradiation was realized, which was mainly because the above-bandgap electrons and holes of the upper nano-PDI relaxed to the edge of the band and converted the excess energy into heat. The unique energy band structure of rGO also promotes the effective photothermal conversion of the composite film. The composite film degraded 94.31 % (10 mg/L) of ciprofloxacin hydrochloride (CIP) under 0.5 sun visible light irradiation within 120 min. The corresponding interfacial steam generation efficiency via photothermal conversion of the composite film was 10.92 %. Furthermore, the composite film retained its excellent photothermal performance, when used to remove CIP from real water samples, including Yellow River water, Weihe River water, and tap water.