Band structure modification of g-C3N4 for efficient heterojunction construction and enhanced photocatalytic capability under visible light irradiation

The graphene (Gr)/PI (pyromellitic dianhydride (PMDA) modified g-C3N4) heterojunction was fabricated by a handy sonochemical method. After adding PMDA in the forming process of g-C3N4, the conduction position of obtained catalyst was lowered to −0.59 eV (closer to the Fermi level of Gr), which is beneficial for constructing high-efficient heterojunction with less energy loss. The photocatalytic efficiency of Gr/PI for Rodamine B (RhB) degradation was greatly enhanced compared with Gr/g-C3N4. The k of RhB removal on Gr/PI was 1.60 times as that of Gr/g-C3N4. The excellent photocatalytic ability of Gr/PI was mainly attributed to the effective separation of photogenerated electron-holes.