Enhanced photocatalytic and antibacterial activities of sol–gel synthesized ZnO and Ag-ZnO

Nanocrystalline ZnO and Ag-ZnO (0.1 at%) have been synthesized by sol–gel method and characterized by X-ray diffraction, energy dispersive X-ray spectrum, scanning electron micrographs and UV–vis diffuse reflectance, photoluminescence and electrochemical impedance spectra. Doping ZnO with Ag reduces the average crystal size, sharpens the band gap absorption and decreases the charge-transfer resistance. The bactericidal and photocatalytic activities of sol–gel synthesized ZnO, tested, respectively, with Escherichia coli and cyanide ion, are larger than those of commercial ZnO nanoparticles. Ag doping by sol–gel method enhances the antibacterial and photocatalytic activities; the latter has been tested using methylene blue, methyl orange and rhodamine B.