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.