Photocatalytic and antibacterial activities of ZnO nanoparticles synthesized by chemical method

In this study, ZnO NPs were synthesized and reporting first time using capping agent SDS with Zn (NO₃)₂ and KOH as precipitating agent. The obtained samples were thoroughly characterized by different techniques like XRD, UV–Vis. DRS, PL, FE-SEM and HR-TEM. The XRD patterns of ZnO NPs (calcined at 300–500 °C) show wurtzite hexagonal nanocrystalline structure. The structural parameters were studied in detail. The bandgap of ZnO NPs calcined at 400 °C is found to be 3.13 eV. The FT-IR spectra represent the characteristic Zn–O–Zn stretching vibrational band. The FE-SEM and HR-TEM images reveal that the ZnO NPs calcined at 400 °C are in spherical shape with 15–20 nm size. The EDS spectrum showed elemental compositions of ZnO NPs with oxygen vacancies. The photocatalytic properties of the calcined samples are investigated by studying the photodegradation of Methyl Orange (MO) which showed a photodegradation efficiency of 92.69% within 120 min under UV–Vis. light (λ = 365 nm). In addition, antibacterial activity of ZnO NPs calcined at 400 °C was studied against five different bacterial strains by agar well diffusion method. The test of antibacterial activity indicated the highest antibacterial activity of ZnO NPs against S. aureus followed by E. coli and B. subtilis.