Photocatalytic Activity of Tetrabutyl Ammonium Hydroxide Modified TiO2 Under Visible Light Irradiation

Tetrabutyl ammonium hydroxide modified TiO2 photocatalyst(TBAH-TiO2) was prepared by a sol-gel method and surface modification method with tetrabutyl ammonium hydroxide (TBAH). The structure, crystallite size and energy levels of the photocatalysts were studied by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) Fourier transform infrared (FTIR) spectroscopy and surface photovoltaic spectroscopy (SPS). The experimental results of 4-chlorophenol photocatalytic degradation showed that TBAH-TiO2 exhibited a better. photocatalytic activity than TiO2. Its photocatalytic efficiency is 2. 6 and 1. 7 times as high as that of pure TiO2 under visible light and ultraviolet light, respectively. The results reveal that NOx(x = 1, 2 and 3) species that exist on the surface of the TBAH-TiO2 catalyst introduce the energy level of surface states 0. 20 eV above the valence band. This energy level not only makes the catalyst responsible to visible light but also promotes the separation of photogenerated carriers. Thus, the activities under ultraiolet light and visible light irradiations are increased.