Controllable synthesis of peapod-like TiO2@GO@C electrospun nanofiber membranes with enhanced mechanical properties and photocatalytic degradation abilities towards methylene blue

Abstract

We prepared peapod-like titanium dioxide@graphene@carbon (TiO₂@GO@C) nanofiber membranes through electrospinning. Due to the porous structure, large surface area, abundant surface functional groups and excellent thermal conductivity, GO can capsulize TiO₂ nanoparticles to form a pea-like TiO₂@GO structure. Subsequently, TiO₂@GO can be wrapped by the carbon nanofiber during an electrospinning process, forming peapod-like TiO₂@GO@C nanofiber membranes. The existence of a peapod-like structure is beneficial for enhancing the crystallinity of TiO₂, and preventing the phase transformation of TiO₂ from anatase to rutile phase at the same time. Furthermore, on the basis of the excellent carrier transport property of GO, the peapod-like TiO₂@GO@C structure could also improve the light absorption, reduce recombination of hole–electron pairs, and improve the carrier transport and finally photocatalytic degradation property of methylene blue. Besides, the pea-like TiO₂@GO structure shows a dispersion strengthening effect in the carbon nanofibers, preventing the carbon nanofibers from fracture. In particular, by optimizing the heat treatment temperature and additional amount of GO, the peapod-like TiO₂@GO@C nanofiber membranes with 0.3 wt% GO show an excellent photocatalytic degradation efficiency of 98.5% in 3 h, and a high strength of 356.07 cN per dtex.