Sodium alkoxide-mediated g-C3N4 immobilized on a composite nanofibrous membrane for preferable photocatalytic activity

Abstract

g-C₃N₄ is a classic photocatalyst not only owing to the metal-free semiconducting electronic structure but also tunable multifunctional properties. However, strategies for chemical exfoliation of g-C₃N₄ based on organic bases have been rarely reported. A family of sodium alkoxide-mediated g-C₃N₄ has been prepared via a simple synthesis. The degradation rate of bulk g-C₃N₄ is 39.8% when irradiation lasts 140 minutes. However, the degradation rate of g-C₃N₄–MeONa, g-C₃N₄–EtONa, and g-C₃N₄–^tBuONa is 55.1%, 68.6%, and 79.1%, respectively, under the same conditions. Furthermore, g-C₃N₄–^tBuONa has been immobilized on flexible electrospun PAN nanofibers to prepare floating photocatalysts. SEM analysis shows that the paper-based photocatalyst PAN/g-C₃N₄–^tBuONa becomes a nanofiber membrane (A4 size, 210 mm × 297 mm). The nanofiber is approximately 350 nm in diameter. Interestingly, once synthesized, the g-C₃N₄–^tBuONa particles move into the spinning solution, where the nanofiber wraps around them to form a monodisperse structure that resembles beads, or knots of 1–2 μm, on a string. The degradation efficiency of 10 mg L⁻¹ MB solution can reach 100% for 2 hours until the solution becomes colorless. In addition, the photocatalytic mechanism studies have been validated. Different from H₂SO₄ or HNO₃, this work has proposed a facile strategy for designing preferable floating photocatalysts using sodium alkoxide.