Self-templating synthesis and photocatalytic activity of hollow TiO2 microspheres prepared by the sol–gel + solvothermal method

•With the increase of Rw in the range of 0.75 ∼ 3.75, TiO2 microspheres with flower-like, hollow and solid structures were prepared by sol–gel and solvothermal methods.•During the solvothermal process, with the formation of TiO2-B layer on the surface of the sphere, the Ostwald ripening process ended.•Dense TiO2 layer leads to intergranular stress during calcination, which limits the grain growth and the crystal phase transition from anatase to rutile.•TiO2 hollow microspheres with larger diameter have better photocatalytic activity.•The specific surface area and light capture performance are the important factors affecting the photocatalysis performance of TiO2 hollow microspheres.