“…At present, the molten salt method has become one of the overriding means to synthesize cyano‐rich g‐C 3 N 4 . Currently, the main method used is to mix two or more alkali metal salts (KCl/LiCl (most), KCl/LiBr, NaCl/LiCl, LiI/KI, LiBr/KBr, KCl/KSCN, KCl/KOCN, LiCl/KSCN, KI/LiI, KCl/NaCl/LiCl) with the precursors (melamine, urea, dicyandiamide, CH 5 N 3 ·HCl, guanidine hydrochloride, NH 4 SCN, carbohydrazide) or synthetic intermediate or original carbon nitride uniformly, [ 33,40,49,56–81 ] and then heat them in a tube furnace (Air, Ar or N 2 ) or muffle furnace to a certain temperature (450–650 °C) to react for a period of time, and then wash off the salts with hot water, and finally obtain the sample by drying. In this process, alkali metal salts can play the role of a class of template agent, speed up the reaction rate, make the sample more homogeneous, improve the crystallinity of the sample, etc.…”