Fabrication of anatase TiO2 tapered tetragonal nanorods with designed {100}, {001} and {101} facets for enhanced photocatalytic H2 evolution

In this study, anatase TiO 2 nanorods with exposed high-energy {100} and {001} facets and low-energy {101} facets were fabricated in the presence of surfactants cetyltrimethylammonium bromide , didecyldimethylammonium bromide, and ammonia via a facile hydrothermal method without the erosive reagent hydrofluoric acid . The particle size and morphology were mainly tuned by regulating the hydrothermal temperature. When the temperature was increased from 150 °C to 180 °C and 200 °C, the length of the nanorods decreased from 700-1000 nm to 400–500 nm and 100–200 nm, respectively. Concurrently, the edges and tops of the truncated tetragonal pyramid of the TiO 2 nanorods became blurry and flattened. The synthesized typical TiO 2 nanorods were then used as photocatalysts , and their performance during the direct generation of H 2 from water was evaluated. The TiO 2 nanorods obtained at 150 °C successfully produced high amounts of H 2 evolution (281.36 μmol) in the presence of methanol as a sacrificial agent under ultraviolet light irradiation for 4 h. The outstanding photocatalytic activity of the nanorods was mainly ascribed to the formation of surface heterojunctions in the edges and corners between adjacent high-energy {001} or {100} facets and low-energy {101} facets. The formed heterojunctions could facilitate charge separation through preferential carrier flow toward the specific facets.