Synthesis, Characterization, Structural, and Optical Properties of Polyvinyl Chloride/Zinc Oxide Nanocomposite Films for Photocatalysis Application

Poly(vinyl chloride) (PVC)/Zinc oxide (ZnO) nanocomposite films were synthesized by the sol-gel (spin coating) method using tetrahydrofuran as a solvent. Structural, Optical properties and photocatalytic activities with different nanosize zinc oxide (ZnO) concentrations (8%, 10% and 20%) have been studied. The samples were characterized by XRD, RAMAN, FTIR, UV-Vis spectrophotometer, and photoluminescence. X-ray diffraction measurements indicated that the average particle size of the ZnO is varying between 17 and 24 nm. Characterization by Raman spectrometry of the nanocomposites studied revealed the additional low-intensity lines which characterize the wurtzite phase of hexagonal ZnO (wurtzite type) in the host matrix (thin film) of PVC and highlights the good crystalline quality (low density of defects) of ZnO nanocomposites. The results of the FTIR infrared spectroscopy analysis of the PVC/ZnO nanocomposites confirmed the presence of peaks characteristic of the vibration of the Zn-O bond. This characterization also shows an increase in the visibility of the absorption band of ZnO with the increase in doping percentages. UV-Vis optical spectra revealed that the optical band of nanocomposites decreases with increasing concentration of ZnO nanoparticles in the PVC matrix. It was found that the band gap is 3.69, 3.64 and 3.52 eV for xZnO/PVC nanocomposites (x: 8%, 10%, and 20%). The photoluminescence spectra of the samples were found to be strong green luminescence. PVC/ZnO nanocomposites have revealed a wide band of luminescence that stretches from visible to near UV. These results confirm the introduction of ZnO in nanoscale form into PVC matrix. The photocatalytic reaction was depicted using MB in the UV-irradiation action of stacked films in methylene blue (MB) solution. The result showed 20ZnO/PVC films gave efficiency to remove MB by 80% at 60 min, similar to the films (8ZnO/PVC) and (10ZnO/PVC), which gave lower efficiency. The occurrence of dye degradation under light might attribute to the high-charge separation of e-h pairs at the interfaces of PVC and ZnO nanoparticles in its excited state under irradiation.