Synergetic tuning of photocatalytic activity and photostability of Ag_3PO_4 via yttrium doping, carbon quantum dots and BiVO_4 for atenolol degradation

摘要

In this study, Y-doped Ag3PO4, carbon quantum dots (CQDs), BiVO4 were used to synthesize Z-scheme Y-Ag3PO4/CQDs/BiVO4. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance spectra (DRS) were employed to probe into the crystalline structure, morphology, optical property and chemical composition of Y-Ag3PO4/CQDs/BiVO4. The kinetic constant of the prepared Y-Ag3PO4/CQDs/BiVO4 was approximately 2.8 times that of pristine Ag3PO4 for atenolol degradation. The degradation of atenolol mainly depended on the excited holes, center dot OH and center dot O-2(-). The photocatalysis mechanism of Y-Ag3PO4/CQDs/BiVO4 conforms to the Z-scheme mechanism deduced by reactive species trapping experiment, electron spin resonance (ESR) and photoelectrochemical measurement (photocurrent response and EIS). The introduction of yttrium, CQDs and BiVO4 significantly promoted the photogenerated carriers separation of Ag3PO4 and inhibited the photogenerated electron-holes pairs recombination of Ag3PO4 during the degradation of atenolol. Oxygen defects caused by the doping of Y3+ into Ag3PO4 were the centers of capture of photogenerated electrons to generate center dot O-2(-), inhibiting the recombination of photogenerated electron-holes pairs and the photocorrosion of Ag3PO4.