Hierarchical (001) facet anatase/rutile TiO2 heterojunction photoanode with enhanced photoelectrocatalytic performance

A hierarchical heterojunction TiO2 photoanode with large surface/body ratio is reported to exhibit high oxidation activity due to the constructing of anatase TiO2 with exposed (0 0 1) facets. The mixed-phase photoanode is fabricated through surfactant-assisted anchoring ultrathin anatase nanosheets on vertically ordered rutile nanorod arrays. This cactaceae-like TiO2 possesses high-exposed (0 0 1) facets outer layer, large specific surface area (375 m(2) g(-1)), efficient photo-to-current conversion (8.2%) and excellent photocatalytic ability to degrade bisphenol A. The greatly promoted photoelectric and photocatalytic performance results from the synergetic effects of the architecture design of high-active (0 0 1) facets and hierarchical heterojunctions. The mechanism analysis reveals that the remarkable increase of photogenerated carrier concentration (2.40 x 10(22) cm(-3)) improves photocatalytic activity, by virtue of constructing staggered energy levels, suppressing the recombination of electrons and holes, and extending the electron lifetime (133 ms). (C) 2013 Elsevier Ltd. All rights reserved.