Synthesis And Photocatalytic Properties Of Nitrogen-doped Layered Tetraitanate Potassium Photocatalyst

In recent years, photochemistry, photocatalysis and catalytic chemistry have been the most active research areas, especially in the photocatalysis field, the light energy transformation into electric energy and chemical energy. Research has shown that layered compound has great potential in catalysis such as the photocatalysis field. Potassium titanate is a typical semiconductor-based layered metallic compound. It has been reported as a photocatalyst for water splitting.In this study, precursor potassium tetratitanate (K₂Ti₄O₉) was prepared the by solid-phase reaction between K2CO3 and TiO2. Protonic layered tetratitanate(H₂Ti₄O₉) was obtained by subsequent acidification of K₂Ti₄O₉ with HCl (1M) solution. The nitrogen-doped photocatalyst was obtained by solid state reaction between H₂Ti₄O₉ and urea, which was served as the source of nitrogen. X-ray diffraction (XRD), infrared spectroscopy (IR), ultraviolet-visible diffuse reflectance spectroscopy (UV-DRs) were used to characterize the prepared material. Results showed that the resulting nitrogen-doped layered K₂Ti₄O₉ compounds had a larger interlayer space than their precursor. UV-Vis diffuse reflectance spectroscopy (UV-DRs) results show that the visible light absorption capacity of nitrogen doped catalysts significantly enhanced. This specific structure of the nitrogen-doped K₂Ti₄O₉(N-K₂Ti₄O₉) led to an enhanced adsorption capacity in visible light wave band compared with its precursor. By IR spectroscopy analysis, it is found that there are chemical reaction that occurs between nitrogen and the potassium titanate skeleton.The photocatalytic degradation of methylene blue was investigated in a self-made photoreactor. The doped nitrogen temperatures play an important role in photocatalytic activity of K₂Ti₄O₉ under UV light and visible light. The results indicated that different temperatures of N-doped photocatalysts result in different depth colour of photocatalysts,and the different ability of light absorption. The Nitrogen-doped H₂Ti₄O₉(N-H₂Ti₄O₉) show better photocatalysis for degradation of methylene blue under visible light wave band than H₂Ti₄O₉; while N-doped K₂Ti₄O₉ show higher electro-photo-catalytic activity in the visible light wave band than its photo-catalytic activity. Compared with the photocatalysis, N-K₂Ti₄O₉ film photoelectrocatalytic on photocatalytic degradation of methylene blue more thoroughly, not only the destruction of their chromophore, but also decomposition of the benzene ring conjugate system.