Well-dispersed mesoporous Ta2O5 submicrospheres were obtained by tailoring the heating rates (R) of calcining Ta2O5 precursor colloidal spheres which were synthesized by the hydrolysis of tantalum glycolate in a mixture of acetone and water. With increasing R, the pore size and the dispersibility of the as-prepared submicrospheres decrease gradually whereas the specific surface area and the pore volume reach maximum values at R = 5 degrees C/min. These phenomena are reasonably explained by the dependence of the temperature gradient within the Ta2O5 precursor colloidal spheres on R, which modulates the nucleation and growth behaviors of the Ta2O5 crystallites during the calcination process. Because of the good dispersibility, unique mesoporosity and high crystallinity, the Ta2O5 submicrospheres obtained at R = 5 degrees C/min show a significantly enhanced photocatalytic activity not only for hydrogen evolution but also for photodegradation of organic pollutants such as methylene blue and rhodamine B. The results here suggest that the meticulous control over the structural characteristics is an effective alternative to obtain highly efficient photocatalytic materials. The as-prepared well-dispersed mesoporous Ta2O5 submicrospheres are promising for the applications in clean energy access and environment remediation. (C) 2013 Elsevier B.V. All rights reserved.