Synthesis, Characterization, and Study of the Photocatalytic Activity upon Polymeric-Surface Modification of ZnO Nanoparticles

Abstract

In this study, ZnO nanoparticles were successfully synthesized through a sol-gel route using zinc acetate precursor, polymer N-Vinylpyrrolidone (PVP), Cetyl Trimethyl Ammonium Bromide (CTAB), and Poly-Ethylene Glycol (PEG). The nanoparticles were examined with Crystal Violet (CV) dye photodegradation under UV irradiation. The addition of polymers controlled size, shape, and morphology of the particles and reduced the formation of agglomerates. The size and crystallinity of polymer/ZnO nanoparticles were analyzed using X-Ray Diffraction (XRD). UV-visible spectroscopy was used to study the optical properties and bandgap of the nanoparticles, while nitrogen adsorption-desorption isotherms were used to analyze their pore structure and surface area. XRD showed that all the lattice constants changed and the bandgap energy declined with the addition of polymers, which can be attributed to the improvement in crystallinity of the polymer specimens. The ZnO bandgap can be tuned in the range of 3.29, 3.251, 3.275, and 3.254 eV, using pure ZnO, CTAB, PEG, and PVP, respectively. All obtained BET isotherms can be classified as type II isotherms, characteristic of nanoporous material. ZnO-pure has high photocatalytic efficiency (69.66%), which was significantly decreased after the surface of the ZnO nanoparticles was capped with PVP (43.16%), PEG (19.82%), and CTAB (14.36%). On the same surface, the catalytic activity of ZnO-PVP was improved by 28% compared to pure ZnO, with a photodegradation efficiency of 97%.