Electrospinning preparation of g-C₃N₄/Nb₂O₅ nanofibers heterojunction for enhanced photocatalytic degradation of organic pollutants in water

In this study, graphitic carbon nitride (g-C₃N₄) and niobium pentoxide nanofibers (Nb₂O₅ NFs) heterojunction was prepared by means of a direct electrospinning approach combined with calcination process. The characterizations confirmed a well-defined morphology of the g-C₃N₄/Nb₂O₅ heterojunction in which Nb₂O₅ NFs were tightly attached onto g-C₃N₄ nanosheets. Compared to pure g-C₃N₄ and Nb₂O₅ NFs, the as-prepared g-C₃N₄/Nb₂O₅ heterojunction exhibited remarkably enhanced photocatalytic activity for degradation of rhodamine B and phenol under visible light irradiation. The enhanced catalytic activity was attributed predominantly to the synergistic effect between g-C₃N₄ sheets and Nb₂O₅ NFs, which promoted the transferring of carriers and prohibited their recombination, confirmed by the measurement of transient photocurrent responses and photoluminescence spectra. In addition, the active species trapping experiments indicated that superoxide radical anion (·O₂^-) and hole (h⁺) were the major active species contributing to the photocatalytic process. With its high efficacy and ease of preparation, g-C₃N₄/Nb₂O₅ heterojunction has great potentials for applications in treatment of organic pollutants and conversion of solar energy.