Facile synthesis of Fe-doped g-C3N4 for enhanced visible-light photocatalytic activity

Fe-doped graphitic carbon nitride (g-C3N4) materials were synthesized by one-step thermal condensation of iron nitrate nonahydrate (Fe(NO3)(3)center dot 9H(2)O) and melamine as precursors. The morphology and crystal structure of the synthesized Fe-doped g-C3N4 samples were verified by XRD, SEM and FT-IR methods. The results reveal that iron species were well dispersed in the structure of g-C3N4 without changing the layered stacking structures, and might intercalate into the layer of g-C3N4 by coordinating to N atoms to form intercalation compounds, thereby affecting the energy band structure, enhancing visible light absorption and electrons-holes separation rate. Especially, the sample with 0.5 wt% Fe exhibited the highest activity in degradation of Rhodamine B under visible light irradiation, indicating that Fe doping could promote the photocatalytic activity of g-C3N4, while excessive Fe might break the sheet structure and inhibit activity. A plausible mechanism for the enhanced photocatalytic activity was proposed from trapping experiments, which emphasized the pivotal role of Fe3+/Fe2+ couple in the photocatalytic reaction.