Visible Light Induced\nPhotocatalytic Degradation of\nDiclofenac in Aqueous Solution Using Fabricated ZnO/g‑C<sub>3</sub>N<sub>4</sub> by Facile Calcination Technique

The ability of the heterojunction between two distinct\nsemiconductors\nwith appropriately matched band gaps to improve the separation of\nphotogenerated electron–hole pairs has been demonstrated to\nenhance photocatalytic activity. Hence, ZnO/g-C<sub>3</sub>N<sub>4</sub> composites have been fabricated by the facile deposition and calcination\nof ZnO and g-C<sub>3</sub>N<sub>4</sub>. X-ray photoelectron spectroscopy,\npowder X-ray diffraction, and Fourier transform infrared spectroscopy\nconfirm the formation of the composite. Scanning electron microscope,\ntransmission electron microscope, and energy-dispersive X-ray spectroscopy\nmorphological analysis reveal that ZnO was homogeneously spread over\nthe g-C<sub>3</sub>N<sub>4</sub> surface. UV–vis diffuse reflectance\nspectroscopy analysis shows the slightly enhanced visible light absorption\nability of the composite. Photoluminescence (PL) spectroscopy and\nelectrochemical impedance spectroscopy analysis prove the higher charge\nseparation of the composite during the irradiation of light. The composite\nshows admirable photocatalytic efficiency in the visible light-driven\nphotocatalytic degradation of an aqueous diclofenac (DFC) solution.\nThe superoxide anion radical (•O<sub>2</sub><sup>–</sup>) and hydroxyl radical (•OH) act as reactive species during\nthe degradation reaction. Probable reaction mechanisms have been proposed.