Photodeposition of Au Nanoclusters for Enhanced Photocatalytic Dye Degradation over TiO Thin Film.

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