Hierarchical (0 0 1) 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 m2 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 × 1022 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).

► (0 0 1) facet TiO2 photoanode with large surface area is reported for the first time.
► Ordered heterojunction further improves light absorption in (0 0 1) facet TiO2 system.
► (0 0 1) facet TiO2 photoanode possesses promoted photoelectrocatalytic performance.
► Photoelectrical enhancement mechanism is clarified by electrochemical methods.
► Photogenerated carrier and lifetime are remarkably enhanced by ingenious design.