In Situ Ti3+/N-Codoped Three-Dimensional (3D) Urchinlike Black TiO2 Architectures as Efficient Visible-Light-Driven Photocatalysts

In situ Ti 3+ /N-codoped 3D urchinlike black TiO 2 (b-N-TiO 2 ) is synthesized via hydrothermal treatment with an in situ solid-state chemical reduction method, followed by annealing at 350 °C in argon. The results indicate that N and Ti 3+ was codoped into the lattice of anatase TiO 2 . The prepared b-N-TiO 2, with a narrow bandgap of ∼2.43 eV, possesses a three-dimensional (3D) urchinlike nanostructure, which is composed of fiberlike architecture with a length of 200–400 nm and a width of 25 nm. The visible-light-driven photocatalytic degradation rate of Methyl Orange and hydrogen evolution rate for b-N-TiO 2 are 95.2% and 178 μmol h –1 g –1, respectively, which are ∼3 and ∼8 times higher than those of pristine TiO 2 . The excellent photocatalytic activity is mainly attributed to synergistic effect of the N and Ti 3+ codoping narrowing the bandgap, and unique 3D urchinlike architecture favors the separation and transport of photogenerated charge carriers and offers more surface-active sites.