Enhancement of photocatalytic activity of TiO2 nanoparticles by silver doping: photodeposition versus liquid impregnation methods

Silver doped TiO2 nanoparticles have been prepared by liquid impregnation (LI) and
photodeposition (PD) methods and characterized by surface analytical methods such as
scanning electron micrographs (SEM) and X-ray diffraction (XRD). The photocatalytic activity
of silver doped TiO2 was tested by photocatalytic degradation of C.I. Acid Red 88 (AR88) as a
model compound from monoazo textile dyes. Results show silver doped TiO2 is more efficient
than undoped TiO2 at photocatalytic degradation of AR88. The positive effect of silver on the
photoactivity of TiO2 at degradation of AR88 may be explained by its ability to trap electrons.
This process reduces the recombination of light generated electron-hole pairs at TiO2 surface.
Silver content has an optimum value 2% in LI and 0.5% in PD methods for achieving high
photocatalytic activity. The AR88 decomposition with Ag-photodeposited method was much
higher than that of deposited with LI method.