rGO supported self-assembly of 2D nano sheet of (g-C3N4) into rod-like nano structure and its application in sonophotocatalytic degradation of an antibiotic

Graphitic carbon nitride (g-C3N4) is an analog of graphite due to its unique electronic structure. g-C3N4 based materials have been used in photocatalytic applications. However, pure g-C3N4 suffers from major shortcomings which include poor disparity, low surface area and a high recombination rate of photo generated electron-hole pairs that significantly reduce its photocatalytic activity. In this work, self-assembly of g-C3N4 sheet into rod shaped g-C3N4 was developed via a simple polymerisation method. A composite made of g-C3N4 nanorods and rGO (rGO-RCN) was also prepared. The band gap g-C3N4 was shifted from 2.77 to 2.6 eV evidented by UV-DRS data. As a result, rGO-RCN showed a relatively high absorption in the visible region. Moreover, a fast electron transfer rate was observed with rGO-RCN composite as conformed from PL analysis and photocurrent measurement. The formation of nanorod and sheet morphologies was confirmed via TEM analysis. The photocatalytic activities of prepared sheet-g-C3N4 (SCN), Rod g-C3N4 (RCN), reduced graphene oxide supported sheet-g-C3N4 (rGO-SCN) and reduced graphene oxide supported Rod-g-C3N4 (rGO-RCN) were evaluated using a commonly used antibiotic (tetracycline). Among these catalysts, rGO-RCN nanocomposite showed sonophotocatalytic activity 3 times higher compared to pure g-C3N4. This superior sonophotocatalytic activity could be due to enhanced visible light absorption of the material, active sites generated by ultrasound, and the high electron transport property of rGO.