Unveiling solar-powered efficiency for methylene blue photodegradation with Ag-doped CeO₂/ZnO nanocomposites

We synthesized Ag-doped CeO₂/ZnO nanocomposites by means of a ethanolic dispersion technique. Several methodologies for characterization were applied to the study of these nanocomposites, such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), UV–visible absorption spectroscopy, and photoluminescence spectroscopy. The composite sample was found to contain wurtzite and cubic phases of ZnO and CeO₂, respectively, according to the XRD examination. A strong bond between CeO₂ and ZnO within the nanocomposite was demonstrated by the SEM and TEM investigations. Moreover, it was discovered that the addition of Ag and the coupling of CeO₂ caused a red-shift and moved ZnO absorption edge from the UV to the visible spectrum. Consequently, the bandgap was reduced from 3.08 eV to 2.69 eV, and the absorbance band intensity increased in the visible region. Utilizing visible light, 15% Ag-doped CeO₂/ZnO nanocomposites exhibit enhanced photocatalytic properties (98.90%) for the degradation of methylene blue (MB) within 60 min. The long-term reliability and recyclability of the photocatalyst were explored through four successive cycles, revealing its persistent and reusable nature. An active radical quenching test was conducted to elucidate the involvement of \({O}_{2}^{\bullet -}\) $O_2^{\bullet -}$ and \({HO}^{\bullet }\) ${\mathit{HO}}^{\bullet }$ radicals, with \({HO}^{\bullet }\) ${\mathit{HO}}^{\bullet }$ radicals identified as the primary species in the photocatalytic breakdown of MB. Ag-doped CeO₂/ZnO nanocomposites, featuring metal ion doping, displayed notable improvements in photodegradation activity, making them well suited for the effective removal of hazardous dyes present in textile effluents.