LAUSR

Abstract The core-shell SrTiO 3 /TiO 2 heterostructure was obtained via a combined hydrothermal route and calcination treatment using amorphous spherical TiO 2 as both template and reactant. Adjusting the hydrothermal environments can control the morphology of the post-calcined sample when it is hydrothermally treated at 180 °C/3 h and 200 °C/6 h, respectively. Following the heat treatment at 700 °C/4 h, the obtained powder illustrates the core-shell heterostructure with a hierarchical surface, and the diameter of the microsphere is about 700 nm. This synthesizing route facilitates the formation of a concentration gradient of SrTiO 3 and TiO 2 , and subsequently constructs a gradient energy level, which helps the samples exhibited an excellent de-colorize activity over the methylene blue. The possible formation mechanism of core-shell SrTiO 3 /TiO 2 heterostructures was proposed to guide the further improvement of their photocatalytic activity.