Phase-separated polyvinylidene fluoride/ZnO composite microspheres as sunlight-driven photocatalysts

Abstract

PVDF-ZnO nanocomposites, prepared through phase separation-assisted nanoprecipitation with varying ZnO concentrations, exhibit enhanced photocatalytic performance against organic dye pollutants. Comprehensive characterization methods, including X-ray diffraction, spectroscopic and microscopic analyses, and thermal stability studies, are employed to assess the microspheres of phase-separated PVDF composites. Band gap analysis and optical characteristics of the nanocomposites are studied using Tauc's plots. The band gap energy of ZnO is determined as 3.47 eV, and the microsphere diameter averages between 0.23 and 0.24 μm. The incorporation of 1–3 wt% ZnO increases the decomposition temperature to approximately 480 °C. Photocatalytic performance tests utilizing various organic dye pollutants such as Methyl Orange (MO), Thymol Blue (TB), and Cresol Red (CR) reveal significant degradation efficiencies of 86 %, 84 %, and 35 %, respectively, under natural sunlight exposure. Despite the reduction in crystallinity of the phase-separated PVDF particles with the addition of ZnO, notable enhancements in the photocatalytic activity are achieved for the composites. Phase separation provides a synergistic interaction between the aligned polymer chains and the ZnO nanoparticles, contributing to the high degradation efficiency. Moreover, the presence of ZnO active photocatalytic sites induces active dye degradation. The study showcases the potentiality of PVDF/ZnO nanocomposites in photocatalytic dye degradation, with recoverability of composite particles from dye solutions, a simple composite development method, and direct exposure to natural sunlight. Significant implications are anticipated in pollution control and environmental remediation through the purification of industrial wastewater.