UTILIZING NITROGEN-DOPED GRAPHENE QUANTUM DOTS TO MODIFY ZnO FOR ENHANCED PHOTOCATALYTIC ACTIVITY IN COMMERCIAL INSECTICIDE DEGRADATION

Abstract

This study investigates the synthesis and application of nitrogen-doped graphene quantum dots (N-GQDs) for enhancing the photocatalytic activity of ZnO in the degradation of insecticide in water. N-GQDs were synthesized via a hydrothermal method using varying nitrogen percentages in citric acid (ranging from 0% to 0.75%), reveal consistent excitation and emission peaks at 350 nm and 440 nm, respectively. Fluorescence characterization indicates that higher nitrogen doping percentages enhance the fluorescence intensity of N-GQDs, suggesting increased photo-generated electron production. FT-IR spectra confirm successful nitrogen doping, with characteristic peaks at 1345 cm⁻¹ attributed to C-N stretching vibrations. Furthermore, UV-V is spectroscopy was employed to analyze the absorbance spectra of
a commercial insecticide (beta-cyfluthrin) in water (concentrations: 100-500 ppm), demonstrating a linear increase in integrated absorbance value with concentration. This underscores the potential of UV-Vis spectroscopy for precise insecticide quantification. Photocatalytic degradation experiments using N-GQD-modified ZnO catalysts showed reduced residual insecticide integrated absorbance value compared to pristine ZnO and GQD-modified ZnO, highlighting enhanced photocatalytic activity of N-GQDs. Photocatalytic degradation experiments indicated that ZnO modified with N-GQDs was more effective than ZnO and ZnO modified with GQDs, with the optimal nitrogen doping level found to be 0.65%. This result demonstrates the potential of nitrogen-doped graphene quantum dots as effective photocatalysts for environmental remediation applications.