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

Abstract

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.

Graphical abstract

Keywords:

• Titanium dioxide
• optical bandgap energy
• photoluminescence
• kinetics
• photocatalytic degradation of methyl orange

Acknowledgement

The research fellowship rendered to M. Malligavathy Rajakumar, University Grants Commission (UGC), New Delhi is acknowledged. The authors thank SAIF, IIT Madras for recording HR-SEM and FT-Raman measurement and also thank IIT, Bombay for recording TEM measurement.