Au nanoparticles decorated titanium dioxide nanotube arrays with enhanced photocatalytic dye degradation under ultraviolet and sunlight irradiation

The aim of this study is to show that the geometry of titanium dioxide (TiO2) nanotubes has an inevitable role in photocatalytic activity. The TiO2 nanotubes were synthesized by anodization technique. Au nanoparticles (AuNPs) were spin-coated onto the surface of these nanotubes. The photocatalytic study was conducted using methylene blue dye under UV light and sunlight. In contrast to the obtained results under UV light irradiation, the sunlight photocatalytic activity of AuNPs-coated TiO2 nanotubes was much higher. The nanotubes showcased improved visible light absorption and sunlight photocatalysis due to the SPR effect of AuNPs. Compared to the as-prepared samples, the nanotubes prepared at 600 s duration had an intrinsic geometry which exhibited high photocatalytic activity under sunlight irradiation. These results indicate that the maximum photocatalytic efficiency of TiO2 nanotubes can be achieved by carefully designing the nanotube geometry.