Synthesis and photocatalytic performance of novel metal-free g-C3N4 photocatalysts

Novel metal-free g-C3N4 photocatalysts with light yellow colors were synthesized by heating melamine precursor at different temperatures. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra (DRS). The effect of calcining temperatures on photocatalytic activities of g-C3N4 samples were investigated based on the decomposition of phenol under visible light irradiation. The DRS spectra revealed that the g-C3N4 had strong absorption in the visible light region. The photocatalytic results indicated that the highest phenol degradation of 92.5% was achieved on the samples heated at 520 °C for 4 h. This study may provide an approach to development of novel metal-free photocatalysts to degrade organic pollutants by using visible light.