In situ growth of boron doped g-C₃N₄ on carbon fiber cloth as a recycled flexible film-photocatalyst

The development of feasible, highly stable and easily recycled metal-free photocatalysts has drawn great attention for wastewater purification. Herein, dip-coating followed with thermal polymerization is developed for in situ growth of boron doped graphitic carbon nitride (BCN) on carbon fiber cloth (CFc) as flexible film photocatalysts. HNO₃ treatment on CFc is used to improve the surface hydrophilicity of CF, which is beneficial for the adsorption and nucleation of BCN precursor on CFc in aqueous solution. Boric acid not only works as the boron source but also causes a porous morphology of BCN due to the gasification of water generated from boric acid decomposition during heating process. Because of the close contact between CFc and BCN, CFc induces BCN to better crystalize. Furthermore, the film-photocatalyst exhibits high mechanical stability and recyclability. The porous sheet-like structures, together with the boron doping and CFc support, can improve light capture, charge separation and transport, and dye adsorption. Our work provides a thinking for component and morphology regulation of film-based flexible catalysts towards reusable photocatalysis under outdoor sunlight.