Black TiO2 nanobelts/g-C3N4 nanosheets Laminated Heterojunctions with Efficient Visible-Light-Driven Photocatalytic Performance

Black TiO₂ nanobelts/g-C₃N₄ nanosheets laminated heterojunctions (b-TiO₂/g-C₃N₄) as visible-light-driven photocatalysts are fabricated through a simple hydrothermal-calcination process and an in-situ solid-state chemical reduction approach, followed by the mild thermal treatment (350 °C) in argon atmosphere. The prepared samples are evidently investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N₂ adsorption, and UV-visible diffuse reflectance spectroscopy, respectively. The results show that special laminated heterojunctions are formed between black TiO₂ nanobelts and g-C₃N₄ nanosheets, which favor the separation of photogenerated electron-hole pairs. Furthermore, the presence of Ti³⁺ and g-C₃N₄ greatly enhance the absorption of visible light. The resultant b-TiO₂/g-C₃N₄ materials exhibit higher photocatalytic activity than that of g-C₃N₄, TiO₂, b-TiO₂ and TiO₂/g-C₃N₄ for degradation of methyl orange (95%) and hydrogen evolution (555.8 μmol h⁻¹g⁻¹) under visible light irradiation. The apparent reaction rate constant (k) of b-TiO₂/g-C₃N₄ is ~9 times higher than that of pristine TiO₂. Therefore, the high-efficient laminated heterojunction composites will have potential applications in fields of environment and energy.