Transparent ZnO crystallized glass ceramics for photocatalytic and antibacterial applications

Abstract

The synthesis of the transparent ZnO crystallized 9.35K2O-9.35CaO-42.05ZnO-23.36B2O3-9.35SiO2-6.54Al2O3 glass was done using a melt-quenching and heat-treatment route. Three different heat treatments were provided to get different amounts of ZnO crystals in the glass matrix. The X-ray diffraction technique confirmed the ZnO crystallization in the glass matrix. Further characterization was performed using Raman and photoluminescence techniques. The bandgap decreased (3.75–3.14 eV) with an increase in ZnO crystallization. The flower-type morphology of ZnO crystallites was observed using a scanning electron microscope. Contact angle measurements showed an increase in hydrophilicity with the increase in ZnO crystallization. During the photocatalytic ink test using smart Resazurin (Rz) ink, ZnO crystallized glass samples cleaned all ink within 5 h. 78% degradation was observed in Rhodamine B dye (pollutant) using one of the ZnO crystallized samples during the photocatalytic dye degradation test, showing its promising photocatalytic properties. ZnO crystallized glasses portrayed good antibacterial property against Escherichia coli (Gram-negative bacteria). Complete depletion of bacteria within 60 min exposure under ultraviolet irradiation was recorded with one of the ZnO crystallized glasses without any external intervention.