Synthesis and study of the physical and photocatalytic properties of composites g-C3N4/ZnO

Abstract

In this study, g-C3N4/ZnO composites were fabricated using an ultrasound mixing method. The physical properties as well as the photocatalytic properties of the materials have been
studied by several techniques such as X-ray diffraction, scanning electron microscopy SEM, ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy PL. The X-ray
diffraction patterns show that the two component phases of the composite material are well crystallized, with no mutual influence on the crystal structure. SEM images show that ZnO
nanoparticles are well dispersed on the surface of g-C3N4 nanosheets, facilitating the process of exchange of charges between two component phases. The intensity of fluorescence spectra decreases as the concentration of ZnO in the composites increases, indicating a decrease in the electron-hole recombination rate facilitating the photocatalytic process. Photocatalytic process under the irradiation of Xenon lamps show a higher photocatalytic efficiency of composite
samples compared to both ZnO and g-C3N4. Composite samples CZ7-3 and CZ6-4 show the largest photocatalyst efficiency, decomposing 100% RhB in solution after 90 minutes of
illumination by Xenon lamps. This can be explained by the decrease of the electron-hole recombination rate as observed in the fluorescence spectra and good contact between two
component phases as in Sem images.