Design of porous silica supported tantalum oxide hollow spheres showing enhanced photocatalytic activity

Abstract

Silica-supported tantalum oxide (ST) hollow spheres were designed for photocatalytic applications in the UV range of 4.1 to 4.8 eV. These nanostructures with a variable diameter of 100–250 nm and shell thickness of 24–58 nm were obtained by the hydrothermal treatment of tantalum isopropoxide and tetraethylorthosilicate at 120 °C for 48 h in the presence of cetyl trimethyl ammonium bromide, which was used as a capping agent. The maximum observed surface area was found to be 610 m²/g and pore size distribution of ST hollow spheres varied from 13.4 to 19.0 nm. Lewis acidity of silica and the contact area between SiO₂ and Ta₂O₅ plays a crucial role in controlling the photocatalytic properties of the ST hollow spheres. We observe a remarkable 6× enhancement in the photoactivity of silica-supported tantalum oxide hollow spheres compared to pure Ta₂O₅.