Abstract:

Nanosized Au/TiO2 catalysts were prepared by the deposition-precipitation method. These catalysts were evaluated by a liquid phase hydrogenation of crotonaldehyde to crotyl alcohol and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). By changing the activation atmosphere, the Au loading, and the reduction temperature we found that the dimension of the Au particles and the metal-support interaction were readily adjustable. For the Au/TiO2 catalyst reduced at 673 K with an optimal Au mass fraction of 9.2%, the mean particle size of Au was 2 nm and the initial hydrogenation rate was as high as 13.7×10-5 mol·s-1·g-1, while the maximum yield of crotyl alcohol was 69.9%. Combined with the characterization results, the superior performance of this catalyst was attributed to it having an optimal size and to its electronic modification effects on the Au nanoparticles. This was due to oxygen defects generated on the TiO2 during the reduction process.

Key words: Selective hydrogenation, Au/TiO2, Preparation parameter, Crotonaldehyde, Crotyl alcohol