Abstract: Mg-Al hydrotalcite-like compounds (Mg-Al-HT) with Mg/Al molar ratio of 2 have been successfully synthesized by a supersaturated precipitation method and then mixed with a titania-sol to prepare nano-crystalline Mg-Al hydrotalcite-like compounds/TiO2 (Mg-Al-HT/TiO2) heterocompound photocatalysts by a hydrothermal method. The structure and components, Brunauer-Emmett-Teller spe-cific surface area, and photoresponse of the photocatalysts were characterized by powder X-ray diffraction, transmission electron micros-copy, field-emission scanning electron microscopy, N2 sorption, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic activity of the nano-crystalline Mg-Al-HT/TiO2 heterocompound photocatalysts for degradation of benzene was superior to that of single TiO2 or Mg-Al-HT under 365 nm light irradiation. The Mg-Al-HT/TiO2 heterocompound photocatalysts had higher stability. The electron paramagnetic resonance (EPR) technique was used to acquire the spin trapped-EPR spectra of the active species in the photocatalytic reac-tion. The possible photocatalytic reaction mechanism was also proposed.

Key words: magnesium-aluminium hydrotalcite-like compound, titanium dioxide, benzene, hetero compound, photocatalysis