From urea to melamine cyanurate: Study of a class of thermal condensation routes for the preparation of graphitic carbon nitride

This work presents a survey of the intermediates in the well-known thermal synthesis of graphitic carbon nitride from urea. The analysis of the crystalline phases depicts a successive transformation of the precursor into different substances previously used as starting reactants, whereby melamine cyanurate arises as the ultimate precursor of a class of thermal condensation routes to obtain graphitic carbon nitride. The study of the optical properties of the synthesized materials evidences the simultaneous production of an amorphous phase with a significant presence of melon oligomers. These results are also supported by the further characterization of the materials performed using THz-TDS, FTIR, HRTEM, and XPS techniques, and by theoretical studies conducted using semi-empirical quantum chemistry methods.

Automated summary

This study presents a survey of the intermediates in the thermal synthesis of graphitic carbon nitride from urea. The analysis of the crystalline phases reveals the successive transformation of the precursor into different substances, and identifies melamine cyanurate as the ultimate precursor for obtaining graphitic carbon nitride. The study of the optical properties of the synthesized materials demonstrates the simultaneous production of an amorphous phase with a significant presence of melon oligomers. These findings are further supported by characterization techniques and theoretical studies.