Enhancement of TiO 2 photocatalytic activity by Gd 3+ doping

Gd³⁺ doped TiO₂ nanopowders were successfully synthesised by sol–gel method using gadolinium nitrate and tetra-n-butyl titanate as the precursors. The as prepared nanopowders were characterised by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicated that Gd³⁺ doping effectively inhibits the phase transformation from anatase to rutile until 700°C, which was propitious to promote the catalytic activity of the catalysts. The fine and uniform Gd³⁺ doped TiO₂ nanopowders with the size of 10–15 nm were obtained using the 0·75 g L⁻¹ hydroxypropyl cellulose (HPC) as dispersant for the excellent steric stabilisation. Compared with the nanocrystalline TiO₂, the Gd³⁺ doped TiO₂ nanopowders exhibited higher photocatalytic activity to methylene blue degradation.