C3N4 is kind of typical non-metal semiconductor material, which can realize electron-hole separation under light excitation. So C3N4 shows extremely high value in the field of photocatalysts. At the same time, C3N4 can be prepared through the process of pyrolysis, using the materials rich in C and N as precursors, such as urea and melamine. So C3N4 also owns the advantage of cheap and economical. As a matter of fact, the morphology of C3N4 is very important for their photocatalytic performance. Therefore, it is of great significance to explore the relationship between the acid concentration used in the process of making C3N4 and the morphology of C3N4. Furthermore, after optimizing the reaction conditions, the Fe3+ was further grafted on the surface of C3N4 to further expand the light absorption capacity of the C3N4 sheet.