Highly efficient ZnO nanostructures for enhanced photocatalytic degradation of organic contaminants under simulated solar light: An efficient industrial approach

Abstract

The increasing demand for uncontaminated and affordable water is now the biggest challenge worldwide. Therefore, there is an urgent need to remove the soluble organic effluents from wastewater and make water reusable. In this aspect, two different morphologies of ZnO nanostructures (NPs and NRs) were developed by a soft-chemical approach and their photocatalytic activity for degradation of organic dyes were investigated. TEM micrographs confirm the formation of nanoparticles (NPs: 20 ± 3 nm) and nanorods (NRs: length of 60 ± 5 nm and width of ∼ 10 nm) of ZnO. XRD and Raman spectra show the formation of single-phase hexagonal wurtzite for both the ZnO nanostructures. The UV–visible absorption and photoluminescence studies confirm that ZnO nanostructures show a change in bandgap and defect concentration as morphology changes from particles to rods. Both the morphologies of ZnO nanostructures show the excellent photocatalytic degradation of methylene blue (MB), rhodamine B (RhB), methyl orange (MO) (under UV and simulated solar light) as well as an industrial dye (under simulated solar light). TheZnO NPs and NRs degrade MB, RhB and MO with 100 % efficiency under UV and solar light at the appropriate time. Moreover, ZnO nanostructures show good photostability and reusability which make them useful for industrial applications.