One-step fabrication and high photocatalytic activity of porous graphitic carbon nitride synthesised via direct polymerisation of dicyandiamide without templates

Porous graphitic carbon nitride (g-C₃N₄) has been synthesised by means of one-step calcinations of dicyandiamide for efficient photocatalysis under visible light irradiation (λ > 400 nm). Scanning electron microscopy images demonstrate that the as-prepared photocatalyst calcined at 650°C is a porous structure. The UV-vis diffuse reflectance spectra show that the optical absorption for the porous g-C₃N₄ is more intensive than for common g-C₃N₄ calcined at 550°C. The enhanced generation of the photocurrent under visible light irradiation (λ > 400 nm) is observed by using the porous g-C₃N₄. The results of the photocatalytic experiments under visible light irradiation reveal that the photocatalytic degradation of methylene blue using the porous g-C₃N₄ is higher than common g-C₃N₄, showing the advantage of the structure for efficient photocatalysis. The presence of the calcinations temperature is presumed to play a key role in adjusting the textural properties.