Enhanced photocatalytic activity from Gd, La codoped TiO2 nanotube array photocatalysts under visible-light irradiation

Well-aligned TiO2 nanotube arrays were successfully synthesized from electrochemically anodic oxidation, which were further codoped by Gd and La via hydrothermal and sol–gel methods. The visible-light photocatalytic activities of the Gd, La codoped TiO2 nanotube arrays evaluated by photodegrading methyl orange (MO) have been significantly enhanced compared to that of undoped TiO2. Hereinto, the photocatalytic performance of Gd, La codoped TiO2 nanotube array synthesized by a hydrothermal approach was better than that by a sol–gel method. A lower band gap energy was attributed to the enhanced response to visible light. The new concept was helpful to guide the synthesis of robust visible-light photocatalysts, and the interesting results suggested that the Gd, La codoped TiO2 nanotube arrays were very promising for elevated the solar utilization in environment management.