UV-blue spectral downshifting role of Ag-doped TiO2 nanoparticles and Ag compound to study its anti-bacterial properties on the E. Coli bacteria

Titanium dioxide nanoparticles (TiO2 NPs) are prepared by using the sol–gel technique at calcination temperatures of 300, 400 and 500 °C. TiO2 NPs prepared at 400 °C are doped with various molar percentages of Ag because of their suitable crystalline and optical properties. Results of UV–Vis adsorption and X-ray diffraction show that the TiO2 NPs’ crystalline structure consists of a mixture of anatase and rutile crystalline phases and calcination temperature play a significant effect on TiO2 NPs structural properties. After the Ag doping of TiO2 NPs, peaks corresponding to TiO and Ag compounds and a pure anatase phase appear in the X-Ray spectrum. UV–Vis adsorption results illustrate the down-shifting of TiO2 NPs doped with Ag, enhancing the photo-catalytic efficiency of Ag-TiO2 NPs. XPS results display significant boarding of Ti 2p peaks related to Ag-TiO2 NPs which may be explained by doping of TiO2 NPs by Ag. The antibacterial property of Ag-TiO2 NPs under various radiation conditions illustrates the significant role of Ag-doped in TiO2 NPs to enhance absorption spectra of sunlight and improvement of photo-catalyst activity of Ag-TiO2 NPs to kill Ecoli-bacteria.