Synergistic effects of Ag inclusion in titania on its photocatalytic activity for the removal of methyl orange

Uniformly distributed Ag nanoparticles are successfully loaded on TiO₂ nanoparticles with different Ag concentration through hydrothermal method. X-ray diffraction pattern and Raman spectra demonstrate the anatase phase of both TiO₂ and Ag/TiO₂. Loading of Ag on the surface of TiO₂ shifts the wavelength of absorption edge to visible light resulting the narrow energy band gap. The photoluminescence intensity decreases with an increase in the concentration of Ag revealing a decrease in the recombination of electron-hole pairs. In order to test them in the photocatalysis, the degradation of textile dye methyl orange is used as a standard. Ag loaded TiO₂ shows better photocatalytic performance than pure TiO₂ because the higher surface area of the nanoparticles enabled them to function as good electron acceptors, delayed the electron-hole pair recombination and surface plasmon resonance of the silver particles. Moreover, 0.1 M of Ag/TiO₂ nanoparticles (AT3) showed higher photocatalytic efficiency of 98.40% within 240 min light irradiation. The superior photocatalytic activity of Ag/TiO₂ is attributed to the interactive effect caused by smaller crystallite size, narrow band gap, large surface area, and also enhancement in the charge separation.