Surface amorphous carbon doping of carbon nitride for efficient acceleration of electron transfer to boost photocatalytic activities

Introducing a built-in electric field (BIEF) has been considered a promising strategy to separate photoinduced electron/hole pairs and to boost the photocatalytic performance of semiconductor photocatalysts. In this work, an amorphous carbon component was formed in-situ and modified on the surface of graphitic carbon nitride (g-C3N4) by copolymerization via a simple green method, in which the amorphous carbon could adjust the band structure and form a BIEF. A variety of measurements, such as X-ray photoelectron spectroscopy (XPS), Mott-Schottky plots and density functional theory calculations, revealed that the BIEF could adjust the intrinsic electronic state and promote photoinduced electron delocalization for the effective separation of carriers in the region, thereby boosting photoelectron transport and improving the reaction kinetics. As a result, the highly photocatalytic activity of CN-PhA30 was demonstrated by degrading bisphenol A (BPA), and the efficiency reached 100% after 80 min of irradiation—a rate that was more than 13 times that of pure g-C3N4. It is worth mentioning that CN-PhA30 also exhibited higher photocatalytic activities for H2 generation and antibiotic degradation. The results showed that the enhanced photocatalytic performance could be attributed to the directional transfer of electrons due to the BIEF formed by amorphous carbon on the surface of g-C3N4.