Abstract: Using TiO₂ and La₂O₃-doped TiO₂ as supports, which were prepared by the sol-gel method, a series of Au catalysts were prepared by the deposition-precipitation method. Their catalytic performance for selective hydrogenation of cinnamaldehyde was tested and their physical and chemical properties were investigated by the techniques of N₂ adsorption-desorption, X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The results show that a moderate amount of La₂O₃ (10%–15%) can obviously improve the catalytic activity and selectivity of Au/TiO₂ for the hydrogenation. The presence of La₂O₃ in TiO₂ increases its surface area, restrains the growth of TiO₂ crystallites, enhances the interaction between Au and support, and makes the particle size distribution of Au crystallites more evenly. The Au on the surface of Au/TiO₂ exists mainly as Au⁰, but on the La₂O₃ doped catalyst there is a small portion of Au³⁺ species besides Au⁰.

Key words: gold, supported catalyst, lanthanum oxide, promoter, cinnamaldehyde, selective hydrogenation, cinnamyl alcohol