Simple Fabrication of PVA–ZnS Composite Films with Superior Photocatalytic Performance: Enhanced Luminescence Property, Morphology, and Thermal Stability

Poly(vinyl alcohol) (PVA)-ZnS composite films were prepared by varying the composition of PVA ranging from 1-5 wt % through a simple solvent casting method. The photocatalytic enactment of the composites was evaluated along with the investigations of their photoluminescence (PL), optical transparency, morphology, and thermal properties. The firm interaction between the ZnS and PVA was confirmed by Fourier transform infrared, UV-vis, and PL spectroscopies. PVA-ZnS composites showed enhanced luminescence property than PVA. The composites exhibited very good optical transparency regardless of the amount of PVA addition. The thermogravimetric analysis data indeed exhibited better thermal stability of the composites. The glass transition temperature ( T g ), melting temperature ( T m ), enthalpy of melting (Δ H m ), and crystallinity were evaluated for such composites. The composites demonstrated morphological variations depending on the amount of PVA addition, although the particle size of ZnS remained similar in the nanometer range (50-120 nm) for all composite samples. The prepared composite films exhibited superior photocatalytic performance in the degradation of methylene blue compared with the bare ZnS and PVA. This study may give a new insight into the fabrication of PVA-ZnS photocatalysts for the treatment of organic pollutants.