In situ generated g-C₃N₄/TiO₂ hybrid over diatomite supports for enhanced photodegradation of dye pollutants

Highlights: • g-C₃N₄/TiO₂@diatomite was fabricated through an in situ deposition method. • The role of diatomite in the formation of composites is discussed. • The enhanced photoactivity is mainly attributed to the high dispersity of catalysts. • The photocatalysts present a potential application in the dye wastewater treatment. The highly efficient g-C₃N₄/TiO₂ heterojunction was deposited over diatomite supports through an in situ deposition process. The microstructure, morphology and optical properties of the novel g-C₃N₄/TiO₂@diatomite composite were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and UV–visible diffused reflectance spectroscopy (UV–vis DRS). The photocatalytic efficiency of g-C₃N₄/TiO₂@diatomite composite was evaluated by the degradation of rhodamine B and methylene blue under visible light and simulated solar light. It is indicated that the as-synthesized g-C₃N₄/TiO₂@diatomite composite displayed higher photocatalytic performance than pure g-C₃N₄ and TiO₂. This enhancement should be ascribed to that diatomite can play as an excellent catalyst carrier to improve the dispersity of g-C₃N₄/TiO₂ and increase the reactive sites for dye pollutants degradation. The CN/T@DE-10% exhibited the highest efficiency towards RhB, which was around 2.5 times under visible light and 3.5 times under solar light as much as that of the pure g-C₃N₄. In addition, the final removal rates of RhB reach to 96% within 3 h under solar light and 83% within 6 h under visible light, respectively. On the other hand, the g-C₃N₄/TiO₂@diatomite composite can be easily separated from suspension and presents a good durability during five cycles. The outstanding properties of g-C₃N₄/TiO₂@diatomite composite and high photocatalytic efficiency make it promising for the potential application in the dye wastewater treatment.