photocatalytic degradation of methylene blue by cu-doped zno/5 wt.% g-c3n4 nanocomposite

Over the last two decades, there has been remarkable progress in the field of photocatalysis. this technology has found significant utility in addressing environmental challenges, particularly in the removal of organic contaminants from both water and air, representing a vital component of advanced oxidation methods. in this research, the synthesis and characterization of a photocatalyst used for the degradation of methylene blue (mb) under visible light irradiation was investigated. the photocatalyst was prepared through a co-precipitation method, incorporating 5 wt. % of graphitic carbon nitride (g-c3n4) within zinc oxide (zno). to further enhance the photocatalytic activity, cu was introduced into the zno/5 wt. % g-c3n4 photocatalyst utilizing the same co-precipitation approach. this novel modification led to the formation of a cu-doped zno/g-c3n4 nanocomposite. the impact of copper incorporation on the photocatalytic performance was systematically investigated. the resultant cu-doped nanocomposite exhibited remarkable potential for efficient mb degradation under visible light irradiation. the photocatalysts' structural and optical properties were assessed using x-ray diffraction analysis, field emission scanning electron microscopy (fesem), and uv-vis spectroscopy. xrd analysis confirmed well-defined crystalline structures of all samples, while fesem revealed unique flaky morphologies with high specific surface areas in g-c3n4 nanosheets and a transition from hexagonal of pure zno to the spherical shape of nanoparticles with the average size of 18.15 nm with the addition of g-c3n4 and cu doping. the drs analysis indicated that the introduction of cu facilitated improved visible light absorption by the nanocomposite, extending its photocatalytic activity into the visible spectrum. additionally, the analysis unveiled a reduction in the bandgap energy within the cu-doped nanocomposite, measuring 2.9 ev, whereas the bandgap energy of pure zno stands at 3.2 ev. the photocatalytic activities of each nanocomposite were evaluated by observing the degradation of mb under visible light exposure. the cu-doped nanocomposite displayed the most rapid degradation rate. it achieved an impressive 84% degradation of mb after 180 min of exposure to visible light, surpassing the performance of the zno/g-c3n4 nanocomposite. the latter achieved a 73% removal of mb within the same timeframe, moreover, a pseudo-first-order kinetic model was employed to evaluate the kinetics of the process. these findings suggest that zno/g-c3n4 photocatalysts hold significant potential for breaking down organic pollutants, and the inclusion of cu as a dopant further enhances their efficiency under visible light. this research contributes to the advancement of photocatalytic materials, which could find valuable applications in environmental remediation and wastewater treatment.