Removing unreacted amino groups in graphitic carbon nitride through residual heating to improve the photocatalytic performance.

In most of the research about graphitic carbon nitride (g-C 3 N 4 ), g-C 3 N 4 is prepared through the calcination of nitrogen-rich precursors. However, such a preparation method is time-consuming, and the photocatalytic performance of pristine g-C 3 N 4 is lackluster due to the unreacted amino groups on the surface of g-C 3 N 4 . Therefore, a modified preparation method, calcination through residual heating, was developed to achieve rapid preparation and thermal exfoliation of g-C 3 N 4 simultaneously. Compared with pristine g-C 3 N 4 , the samples prepared by residual heating had fewer residual amino groups, a thinner 2D structure, and higher crystallinity, which led to a better photocatalytic performance. The photocatalytic degradation rate of the optimal sample for rhodamine B could reach 7.8 times higher than that of pristine g-C 3 N 4 .