Synthesis, characterization and photocatalytic performance of polyvinyl alcohol/zinc oxide nanocomposites: A comprehensive study

Abstract

The present work presents a detailed study on the synthesis and characterization of ZnO and PVA/ZnO nanoparticles using a bottom-up chemical precipitation method. The study found that the incorporation of polyvinyl alcohol (PVA) in ZnO induced a reduction in the XRD peak intensity due to mixed phases on the surface of the nanoparticles. Both ZnO and PVA/ZnO nanoparticles exhibited a non-uniform size distribution below 50 nm, with PVA/ZnO showing a higher dislocation density and microstrain distribution. Using deformation models, Young's modulus equation revealed that PVA/ZnO experiences higher stress values, but also possesses a greater energy density than pure ZnO. The optical properties of the ZnO and PVA/ZnO nanoparticles exhibited bandgaps of 3.14 and 3.09 eV, respectively. The refractive index was found to be influenced by the electronic structure of the material, which wasin turn governed by the bandgap. PVA passivation enhanced the optical quality of ZnO by reducing the non-radiative recombination of charge carriers, leading to improved absorption and higher optical density. TEM analysis revealed that the nanoparticles are polycrystalline and have a pebble-like shape with a size distribution that is less than 49 nm. The study compared the photocatalytic efficiency of PVA/ZnO and pure ZnO nanoparticles in the degradation of crystal violet dye and found that PVA/ZnO exhibited a slightly lower efficiency (48 %) compared to pure ZnO (49 %) after 90 min, with reaction rates of 0.00694 and 0.00747, respectively, indicating a comparable performance despite the presence of PVA. The study exhibits promising applications in optoelectronic-driven environmental remediation processes.