Abstract
Composite photocatalyst based on in situ-grown ZnO particles on graphitic-carbon nitride (g-C
3
N
4
) layers is developed via hydrothermal process. The crystalline phase and chemical state of materials integrated in the composite is confirmed via X-ray diffraction and X-ray photoelectron spectroscopy studies, which indicated the formation of impurity and relatively defective systems. The irregular morphology with average particle size of 100 nm for ZnO and layered structure of g-C
3
N
4
is observed via high-resolution transmission electron microscopy images. The observed ultraviolet (UV)–Vis absorption profile represented the synergistic optical enhancement in the system due to the amalgamation of materials with narrow (g-C
3
N
4
) and wide (ZnO) bandgap structures. The photocatalytic efficiency of the developed g-C
3
N
4
/ZnO composite is examined for its ability to degrade methylene blue, rhodamine B and ciprofloxacin molecules and found degrading ~ 100, 98 and 96% of molecules at the end of 50, 100, and 180 min, respectively. The scavenger studies indicated that the superoxide anions are the key radicals and followed by hydroxyl radicals for the observed superior degradation efficiency of the composite. It is proposed based on the observed results that the formed g-C
3
N
4
/ZnO composite follows the direct Z-scheme mechanism for the charge transfer and photoredox reactions for the effective degradation of various pollutants. The reusability studies up to 5 cycles demonstrated that the developed g-C
3
N
4
/ZnO composite is sustainable for the industrial photocatalytic applications.