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

[Display omitted] • g-C 3 N 4 synthesized by microwave, thermal and solvothermal methods. • Morphology and surface area changed by changing synthesis method. • Sheets obtained by thermal, particles obtained by solvothermal and nanofibers by microwave method. • Microwave prepared g-C 3 N 4 has the highest photocatalytic activity for phenol and MO degradation. Graphitic carbon nitride (g-C 3 N 4) 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-C 3 N 4 nanomaterials were investigated by various techniques. The results demonstrated the successful synthesis of g-C 3 N 4 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 °C, and irregular particles were obtained from the solvothermal synthesis by heating melamine and cyanuric chloride for 16 hrs. at 180 °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-C 3 N 4 materials have shown better solar light photocatalytic performance compared to TiO 2 nanoparticles. This has been directly correlated to the narrower band gab energies of g-C 3 N 4 materials (E g(TGCN) = 2.8 eV, E g(SGCN) = 2.4 eV, E g(MGCN) = 2.45 eV) compared to TiO 2 (3.1 eV). Moreover, the photocatalytic activity of microwave prepared g-C 3 N 4 (MGCN) is about 2 times higher than those prepared by the other methods (TGCN & SGCN) and ∼ 7 times higher than that of TiO 2. This can be readily related to the modified fibrous structure and the highest surface area of MGCN (31.84 m2/g) compared to other materials. [ABSTRACT FROM AUTHOR]