Controllable Synthesis of Phosphorus-Doped Graphitic Carbon Nitride via a Simple Phosphorus Compound Towards Enhanced Visible-Light Photocatalytic Performance

Introduction of phosphorus into graphitic carbon nitride (g-C3N4 or CN) has been demonstrated to be an effective route to improve the photocatalytic activity of CN. Many efforts have been made to synthesize phosphorus-doped CN (PCN) by using different phosphorous precursors, but they are usually composed of at least four elements, which may lead to an increase in uncontrollable factors and environmental pollution in the thermal polymerization process. Herein, PCN photocatalysts were successfully prepared by using a simple inorganic precursor of phosphorus pentoxide as the phosphorous source. Under optimized conditions, PCN photocatalyst shows a visible light (lambda>400 nm) photocatalytic rhodamine B degradation rate of 6.8 times higher than that obtained for the pure CN. Based on the measurements and analyses of ultraviolet-visible diffraction reflectance spectra, photoluminescence spectra, transient photocurrent response and electrochemical impedance spectroscopy, upon the incorporation of phosphorus, the visible light absorption and generation and separation of photogenerated electron-hole pairs are enhanced dramatically compared with pure CN, which may be responsible for the photocatalytic activity improvement of PCN. This work provides a facile, environment-friendly and controllable way to design and synthesize highly effective CN for solar energy utilization and environmental remediation.