Hierarchical Nanotubular Anatase/Rutile/TiO2(B) Heterophase Junction with Oxygen Vacancies for Enhanced Photocatalytic H2 Production.

Oxygen vacancies have been demonstrated to enhance the interfacial charge separation in TiO2-based photocatalysts. In this report, we explored a facile route to synthesize hierarchical nanotubular anatase/rutile/TiO2(B) nanostructures with high surface area and defective electronic structure. The formation of oxygen vacancies in the heterophase junction was analyzed by UV-vis absorption spectra, electron spin resonance, and X-ray photoelectron spectroscopy. The enhanced interfacial charge separation and transportation ensured the excellent photoactivity of oxygen-deficient junctions for the photocatalytic production of hydrogen. As a result, the defective anatase/rutile/TiO2(B) junction showed a high hydrogen evolution rate of 2.79 mmol/h, which was 19 times higher than blank TiO2 nanotubes. The results demonstrate that defect modulation is a powerful tool to enhance the catalytic performances of TiO2-based photocatalysts.