Hydrogenated Cagelike Titania Hollow Spherical Photocatalysts for Hydrogen Evolution under Simulated Solar Light Irradiation

Abstract

We synthesized the hydrogenated cagelike TiO2 hollow spheres through a facile sacrificial template method. After the hydrogenation treatment, the disordered surface layer and cagelike pores were generated on the shell of the hollow spheres. The spheres exhibit a high hydrogen evolution rate of 212.7 ± 10.6 μmol h–1 (20 mg) under the simulated solar light irradiation, which is ∼12 times higher than the hydrogenated TiO2 solid spheres and is ∼9 times higher than the original TiO2 hollow spheres. The high activity results from the unique architectures and hydrogenation. Both the multiple reflection that was improved by the cagelike hollow structures and the red shift of the absorption edge that was induced by hydrogenation can enhance the ultraviolet and visible light absorption. In addition, the high concentration of oxygen vacancies, as well as the hydrogenated disordered surface layer, can improve the efficiency for migration and separation of generated charge carriers