Investigation of structural, chemical formation and oxidation states of Cu-doped titania and WO₃ co-doped titania nanocomposite for antibacterial activity

Cu-TiO₂ and Cu-TiO₂/WO₃ nanoparticles were prepared using sol-gel processing followed by a simple soaking technique. The structural, morphological, and chemical interactions and oxidation states were characterized using X-ray diffraction, field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopic (XPS). The XRD patterns confirmed the presence of the tetragonal anatase phase and also the WCuT45 and WCuT60 nanoparticles exhibited minor tungsten oxide peaks along with major titania peaks. FESEM reveals that the grains in each nanoparticle are semi-spherical in shape, with the average grain size of WCuT45 nanoparticle being lower than the other nanoparticles. The grains of each nanoparticle form agglomeration which resembles cauliflower. FTIR spectroscopy is used to examine the chemical formation and interactions of the nanoparticle components. The XPS confirmed that the peak binding energy of WCuT45 at 951.5 eV is lower than the peak of WCuT15 at 952.2 eV. The two distinct binding energy peaks, 932.4 eV for Cu 2p^3/2 and 951.5 eV for Cu 2p^1/2, show that Cu was incorporated into the CuT lattice and is also present in TiO₂ as Cu²⁺ ions. The antibacterial activity confirms that the WCuT45 nanoparticle’s larger inhibitory zone against bacterial growth is attributed to the formation of electron-hole pairs to assess their ability to kill the bacteria in water.