Effect of pyrolysis conditions on the physicochemical properties of graphitic carbon nitride for visible-light-driven photocatalytic degradation

Graphitic carbon nitride (g-C₃N₄) is an attractive photocatalyst, however, its practical photocatalytic applications are still faced with huge challenges. The aim of this research is to identify the correlation between synthetic conditions and properties of the g-C₃N₄ and derive an optimum synthesis condition for improving photocatalytic activities of the g-C₃N₄. In this study, novel and versatile g-C₃N₄ nanosheets were synthesized by the simple thermal pyrolysis of urea. In the synthesis process, the pyrolysis temperature and the heating rate, which can have the most significant influence on the structures and properties of g-C₃N₄, were set as variables, and the effects were systematically investigated. When synthesized at a relatively high temperature, the amount of material being synthesized is reduced, however it has been found to represent optical properties suitable for highly efficient photocatalyst by the increase in the thickness and defects formed in the g-C₃N₄ nanosheets. The photocatalytic degradation experiment of MB dyes indicated that the highest degradation of 95.2% after the reaction for 120 min was achieved on the g-C₃N₄ nanosheets synthesized at 650^oC.