Exploring the evolution patterns of melem from thermal synthesis of melamine to graphitic carbon nitride.

In the exploration of synthesizing graphitic carbon nitride (g-C 3 N 4 ), the existence of secondary anime bridging units shows the incompleteness of related theories. Thus, taking the thermal synthesis of melamine as an example, this work finds a possible reaction path with Density Functional Theory (DFT) for forming melem during the thermal synthesis of g-C 3 N 4 . Combined with transition state theory (TST), it indicates that the formation of melem results from the condensation of melamine and isomerization of melam. Meanwhile, the weak signal near 2135 cm -1 in the Fourier Transform Infrared Spectra (FTIR) corresponds to the vibration of carbodi-imines (-N[double bond, length as m-dash]C[double bond, length as m-dash]N-), which further proves the proposed reaction path. Thus, this work can explain the formation of g-C 3 N 4 and its monomer, which may contribute to the successful formation of ideal g-C 3 N 4 in the future.