Photo-deposition of Au Nanoclusters for Enhanced Photocatalytic Dye Degradation over TiO2 Thin Film.

Au nanoparticles (NPs) decorated heterogeneous TiO2 catalysts are known to be effective in the degradation of various organic pollutants. The photocatalytic performance of such Au-TiO2 structures remarkably depends on size, morphology and surface coverage of Au NPs decorating TiO2. Here we propose an effective way of preparing highly active Au nanoclusters (NCs) decorated TiO2 thin film by a novel photo-deposition method. By altering the solvent type and as well as the illumination time we achieved well-controlled surface coverage of TiO2 by Au NCs, which directly influences the photocatalytic performance. Here Au NCs coverage affects both the electron store capacity and the optical absorption of the hybrid Au-TiO2 system. At low surface coverage, 19.2-29.5 % Au NCs seem to enhance significantly the optical adsorption of TiO2 at UV wavelengths therefore leads to a higher photocatalytic performance.