Piezocatalytic effect and mechanism of rGO/PVDF-HFP porous film driven by water flow

Water flow-driven piezocatalysis can be applied in self-powered water purification. The polyvinylidene fluoride (PVDF) film with excellent piezoelectric performance, flexibility, easy largescale fabrication, and recycling convenience has great application potential in the self-powered purification for the environment. However, it exhibits low piezocatalysis performance due to its high insulation. The effect of charge enhancement on the PVDF piezocatalysis improvement has not yet been revealed. In this work, porous poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) films were prepared by phase separation processes, and reduced graphene oxide (rGO) as the charge supplier was added into the film. A highly efficient piezocatalysis for 60 % dye waster (methyl orange) decomposition was observed after 300 min by the 10 wt% rGO/PVDF-HFP porous film with 300 rpm magnetic stirring. The roles of the piezoelectric field and charges in the degradation by rGO/PVDF-HFP are revealed by a comparative experiment. The charge supply process by rGO under the piezoelectric field is carefully discussed herein through the rGO band structure. This design strategy of adding rGO to improve the PVDF piezocatalysis provides a new insight into the design of a large and flexible piezocatalyst film driven by the mechanical energy from the environment.