Microwave synthesized g-C3N4 nanofibers with modified properties for enhanced solar light photocatalytic performance

Graphitic carbon nitride (g-C3N4) nanomaterials have been eco-friendly synthesized using microwave and compared to the materials prepared by conventional thermal and solvothermal methods. The properties of as-synthesized g-C3N4 nanomaterials were investigated by various techniques. The results demonstrated the successful synthesis of g-C3N4 either by conventional or microwave methods. However, morphology and surface area have been changed by changing the method used. While small sheets were obtained using thermal decomposition of melamine for 4 hrs. at 500 degrees C, and irregular particles were obtained from the solvothermal synthesis by heating melamine and cyanuric chloride for 16 hrs. at 180 degrees C, nanofibers structure with the largest surface area was obtained by microwave irradiation of melamine and cyanuric chloride for 1hr. The photocatalytic performance of the synthesized materials has been assessed for the decomposition of phenol and methyl orange (MO) dye. All prepared g-C3N4 materials have shown better solar light photocatalytic performance compared to TiO2 nanoparticles. This has been directly correlated to the narrower band gab energies of g-C3N4 materials (E-g(TGCN) = 2.8 eV, E-g(SGCN) = 2.4 eV, E-g(MGCN) = 2.45 eV) compared to TiO2 (3.1 eV). Moreover, the photocatalytic activity of microwave prepared g-C3N4 (MGCN) is about 2 times higher than those prepared by the other methods (TGCN & SGCN) and similar to 7 times higher than that of TiO2. This can be readily related to the modified fibrous structure and the highest surface area of MGCN (31.84 m(2)/g) compared to other materials.