Water flow-driven high piezo-photocatalytic efficacy in superthin and densely porous GO-TiO2/PVDF-HFP composite film for ROS generation

Reactive oxygen species (ROS) as highly oxidative substances play significant roles in environmental matter cycling. Despite their high potential in environmental regulation, effective artificial ROS generation techniques are still in the primary stage. In this study, we propose an effective piezo-photocatalytic film for ROS generation in water flow and under light irradiation. The high ROS generation capability stem from the special suprathin and highly porous structure obtained using our developed spray-drying technique to prepare the composite film. During the spray process, optimized component of graphene oxide, TiO 2 nanoparticles, and Poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) polymer chains self-organized to effective piezoelectrically and photocatalytically active assemblies, and highly porous structures are formed during the drying process. Especial mechanical sensibility to deform is realized in response to external force as weak as 0.2 N. The enhanced piezoelectricity of the PVDF-HFP microdomain, the narrowed band gap, and the electron transfer across the interfacial heterojunction between graphene and TiO 2 all contribute to the especially high piezo-photocatalytic capabilities. Water flow can effectively trigger the piezoelectric field generation in the film, which remarkably boost extractable charge carriers generated upon light irradiation. 88.05 % degradation efficiency of Rhodamine B during 15 min and 95.2 % degradation efficiency of ciprofloxacin in 120 min are realized, along with bacteriostat capabilities. The application potential of the composite are demonstrated in dest-top laundry process and the treated stained water can be used to cultivate plant. We expect the strategy to develop into a novel form of cleaning technique.