Ag and CuO impregnated on Fe doped ZnO for bacterial inactivation under visible light

Interfacial coupling of semiconductor with metal has been demonstrated for inactivation of E. coli. Fe doped ZnO was synthesized by sol-gel method that resulted in enhanced absorbance in visible region. Various concentrations of Cu were impregnated on Fe doped ZnO that eventually turned into copper oxide and the photocatalytic activity of this material was compared with noble metal (Ag) impregnated on Fe doped ZnO. The obtained materials were characterized by various techniques. The crystal structures were determined by XRD and XPS was used to identify the oxidation states of the elements present in the photocatalyst. The morphologies and microstructures were determined by SEM. The optical absorbance of the photocatalysts was characterized by diffused reflectance spectra. Photocatalytic experiments were conducted for inactivation of E. coli using various catalysts. The rate constants obtained for 3 wt.% Cu impregnated Fe doped ZnO was higher than 1 wt.% Ag impregnated Fe doped ZnO. The higher photoactivity of these materials compared to pristine ZnO can be attributed to decreased recombination of the excitons in the synthesized photocatalysts that was validated by photoluminescence. This study indicates the possible employment of copper as a viable substitute for silver for anti-bacterial applications