SEM images of different precursors and calcined C₃N₄ samples: (A) TCN-C, (B) TCM-C, (C) TCN-E, (D) TCN-E. Adapted with permission from [57]. Copyright 2019, Elsevier. (E) Schematic representation of MCA transformation from DMSO to less polar solvent. (F–H) SEM images of MCA aggregates after treatment with less polar solvent, (F) methanol, (G) ethanol, and (H) acetone. Adapted with permission from [39]. Copyright 2016, Elsevier. SEM images of C₃N₄ layer stripped by (I) methanol, and (J) ethanol. SEM images of C₃N₄ inserted by (K) glycol, and (L) glycerol. Adapted with permission from [49]. Copyright 2019, American Chemical Society.