Photodeposition of Au Nanoclusters for Enhanced Photocatalytic Dye Degradation over TiO₂ Thin Film

Au nanoparticle (NP) 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 the size, morphology, and surface coverage of the Au NPs decorating TiO₂. Here we propose an effective way of preparing a highly active Au nanocluster (NC) decorated TiO₂ 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 TiO₂ 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–TiO₂ system. At low surface coverage, 19.2–29.5%, the Au NCs seem to enhance significantly the optical adsorption of TiO₂ at UV wavelengths which therefore leads to a higher photocatalytic performance.