摘要
In this study, nitrogen-doped graphene quantum dots (NGQD) decorated CuWO 4 nanocomposite (NGQD-CuWO 4 ) were synthesized for enhanced photocatalytic tetracycline (TC) degradation under visible light irradiation. The incorporation of NGQDs significantly increased light absorption, narrowed the band gap, and improved charge transfer in CuWO 4 , leading to enhanced photocatalytic efficiency. TEM analysis confirmed the successful integration of NGQDs with CuWO 4 , showing uniform dispersion and lattice fringes, while Raman spectra revealed the characteristic D and G bands of NGQDs, indicating their graphene-like properties. The optimal NGQD loading (3NGQD-CuWO 4 ) achieved a degradation efficiency of 99 % within 90 min, exhibiting a three-fold increase in performance compared to pure CuWO 4 . Photocurrent measurements indicated that incorporating NGQD enhanced the charge separation in CuWO 4 displaying the highest photocurrent density. The lowest charge transfer resistance observed in the hybrid photocatalyst is confirmed by electrochemical impedance spectroscopy (EIS), indicating the significant role of NGQD in increasing the charge transfer kinetics. Optical studies further demonstrated a significant red shift in the absorption spectrum and a reduction in the band gap from 2.43 eV for pure CuWO 4 to 2.29 eV for the 3NGQD-CuWO 4 composite. Kinetic studies indicated a pseudo-first-order reaction with a rate constant three times higher for NGQD-CuWO 4 compared to CuWO 4 alone. Hydroxyl radicals ( • OH) were identified as the main reactive species responsible for degradation. This work highlights that NGQD incorporation makes CuWO 4 an efficient, stable, and promising photocatalyst for environmental applications, particularly in treating pharmaceutical-contaminated water.