Piezoelectric field enhanced photocatalytic efficiency of PVDF/TiO2 core/shell nanofibrous membrane via coaxial electrospinning

Polyvinylidene fluoride (PVDF)/titanium dioxide (TiO2) core/shell composite nanofibrous membranes (CNMs) with large surface area and abundant reactive sites were prepared via coaxial electrospinning, showing an excellent photocatalytic degradation of phenol in a liquid phase. Coaxial electrospinning has been chosen as a versatile and one-step approach in the preparation of this active media, where TiO2 nanoparticles (NPs) are immobilized on the surface of PVDF, which exhibits piezoelectric properties if properly stimulated. Indeed, the air flow in the reactor enhanced the photocatalytic activity of PVDF/TiO2 CNM under UV irradiation, which was less evident for polyacrylonitrile/TiO2 CNM, TiO2 NPs, and neat PVDF membrane, owing to the piezo-potential field generated on the PVDF core-fibers. ∙OH and h+ were the main active species, while O2−∙ and e− played a relatively weak role, in the photo-oxidation of the tested organic compound. This flexible and recoverable PVDF/TiO2 membrane has shown to be a good candidate for promoting advanced piezo-photocatalytic properties and its practical applications for wastewater treatment.