Enhanced photocatalytic activities of Nd-doped TiO2 under visible light using a facile sol-gel method

Titanium dioxide nanoparticles modified with neodymium in the range of 1 mol% to 5 mol% were prepared with template-free sol-gel method. The structures of obtained samples were characterized by X-ray powder diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and diffuse reflectance spectroscopy. The photocatalytic activity of the obtained samples was evaluated by photodegradation of methyl orange in aqueous solution under ultraviolet-visible (lambda > 350 nm) and visible (lambda > 420 nm) irradiation. The experimental results show that the 1 mol% Nd-doped TiO2 exhibits the highest photocatalytic activity, of which the degradation can reach to 96.5% under visible irradiation. According to the XRD results, the pristine samples are combined with anatase TiO2 and rutile TiO2, while the Nd-doped TiO2 samples are anatase TiO2 only. This transformation has made an obvious promotion of photocatalyst activity after modification. (C) 2020 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.