An Assessment of the Antibacterial Activity of Ag- Doped TiO2 and Ag-Doped ZnO Nanoparticles

This work presents the antibacterial activity of Ag-doped TiO2 and Ag-doped ZnO nanoparticles (NPs) that were synthesized using a sol-gel method and tested under visible light irradiation. The structural, morphological characteristics of synthesized nanoparticles were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) spectrum. X-ray diffraction analysis indicated that Ag-doped TiO2 comprised both rutile and anatase phases. The presence of the hexagonal wurtzite structure was detected in Ag-doped ZnO nanoparticles. The altered morphologies of TiO2 and ZnO by the doping of Ag was demonstrated by the TEM. EDX analysis verified the presence of zinc (Zn), titanium (Ti), silver (Ag), and oxygen (O) components in the samples. Pathogenic bacteria, such as Bacillus subtilis, Escherichia coli, were used to determine the antibacterial activity of the synthesized nanoparticles. It was observed that both the synthesized nanoparticles Ag-TiO2 and Ag- ZnO NPs exhibited antibacterial activity against gram-positive bacteria Bacillus subtilis and gram-negative bacteria Escherichia coli, however Ag-ZnO NPs exhibited higher antibacterial activity compared to Ag-TiO2 NPs.