Ag-catalyzed strain engineering in ZnO for tailoring defects towards bacterial inactivation and removal of organic dyes for environmental sustainability

Abstract

This study explored Ag-guided strain formation in ZnO that can manipulate defects in related properties, which are helpful in enhancing the photocatalytic performance of ZnO. Ag@ZnO nanosheets were synthesized with varying Ag concentrations (0–5 at%) through a cost-effective hydrothermal method and employed for the efficient removal of environmentally concerning dyes, namely methylene blue (MB), methyl orange (MO), and rhodamine B (RhB), under natural sunlight radiation. Microscopic images (SEM and TEM) revealed the nanoplates regardless of the Ag concentrations. The XRD pattern confirmed the pure phase of the hexagonal wurtzite structure of ZnO, while the crystallite size decreased from 25 to 20 nm, augmented with the bright field-TEM images. The energy bandgap, Eg, decreased from 3.24 to 3.18 eV, as Ag concentration increased from 0 to 5 at%. The highest photocatalytic efficiency of Ag@ZnO:5 at% was achieved to be ∼93 %, ∼97.5 %, and ∼98 % for MO, MB, and RhB, respectively. The enhanced photocatalytic activity of Ag@ZnO:5 at% was attributed to the high charge separation efficiency and many active sites due to the surface integration of Ag atoms and defects states. Ag@ZnO:5 at% nanoplates showed significant inactivation against environmentally transmitted pathogenic bacteria within 30 min. These findings underscore the significant potential of Ag@ZnO photocatalysts for sunlight-driven removal of organic pollutants, aligning with the sustainability goals advocated by the United Nations. The outcomes of this research contribute valuable insights into the development of efficient photocatalytic materials for environmental pollution remediation.