Steered polymorphic nanodomains in TiO₂ to boost visible-light photocatalytic oxidation

A breakthrough in enhancing visible-light photocatalysis of wide-bandgap semiconductors such as prototypical titania (TiO₂) via cocatalyst decoration is still challenged by insufficient heterojunctions and inevitable interfacial transport issues. Herein, we report a novel TiO₂-based composite material composed of in situ generated polymorphic nanodomains including carbon nitride (C₃N₄) and (001)/(101)-faceted anatase nanocrystals. The introduction of ultrafine C₃N₄ results in the generation of many oxygen vacancies in the TiO₂ lattice, and simultaneously induces the exposure and growth of anatase TiO₂(001) facets with high surface energy. The photocatalytic performance of C₃N₄-induced TiO₂ for degradation of 2,4-dichlorophenol under visible-light irradiation was tested, its apparent rate being up to 1.49 × 10^-2 min^-1, almost 3.8 times as high as that for the pure TiO₂ nanofibers. More significantly, even under low operation temperature and after a long-term photocatalytic process, the composite still exhibits exceptional degradation efficiency and stability. The normalized degradation efficiency and effective lifespan of the composite photocatalyst are far superior to other reported modified photocatalysts.