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

In this study, anatase TiO2 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 degrees C to 180 degrees C and 200 degrees 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 TiO2 nanorods became blurry and flattened. The synthesized typical TiO2 nanorods were then used as photocatalysts, and their performance during the direct generation of H-2 from water was evaluated. The TiO2 nanorods obtained at 150 degrees C successfully produced high amounts of H-2 evolution (281.36 mu mol) 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. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.