Visible Light-Driven Photocatalytic Performance of N-Doped ZnO/g-C₃N₄ Nanocomposites

N-doped ZnO/g-C₃N₄ composites have been successfully prepared via a facile and cost-effective sol-gel method. The nanocomposites were systematically characterized by XRD, FE-SEM, HRTEM, FT-IR, XPS, and UV-vis DRS. The results indicated that compared with the pure N-doped ZnO, the absorption edge of binary N-doped ZnO/g-C₃N₄ shifted to a lower energy with increasing the visible-light absorption and improving the charge separation efficiency, which would enhance its photocatalytic activity. Compared with the pure g-C₃N₄, ZnO, N-doped ZnO and the composite ZnO/g-C₃N₄, the as-prepared N-doped ZnO/g-C₃N₄ exhibits a greatly enhanced photocatalytic degradation of methylene blue and phenol under visible-light irradiation. Meanwhile, N-doped ZnO/g-C₃N₄ possesses a high stability. Finally, a proposed mechanism for N-doped ZnO/g-C₃N₄ is also discussed. The improved photocatalysis can be attributed to the synergistic effect between N-doped ZnO and g-C₃N₄, including the energy band structure and enhanced charge separation efficiency.