A convenient method to prepare a novel alkali metal sodium doped carbon nitride photocatalyst with a tunable band structure

A novel alkali metal sodium doped carbon nitride photocatalyst with a tunable band gap was prepared using dicyandiamide monomer and sodium hydrate as precursors. X-ray diffraction (XRD), N2 adsorption, UV-vis spectroscopy, scanning electron microscopy (SEM), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared catalysts. The CB and VB potentials of graphitic carbon nitride could be tuned by controlling the sodium concentration. In addition, sodium doping inhibited the crystal growth of graphitic carbon nitride, enhanced the surface area and increased the separation rate of photogenerated electrons and holes. The visible-light-driven Rhodamine B (RhB) photodegradation and mineralization performances were significantly improved after sodium doping. The possible influence mechanism of sodium concentration on the photocatalytic performance is proposed.