Effect of preparation method on the catalytic activity of Au/CeO2 for VOCs oxidation

The Au/CeO2 catalysts were synthesized by co-precipitation (CP), deposition-precipitation (DP) and metallic colloids deposition (MCD) method, and tested for oxidation of volatile organic compounds (VOCs). It was revealed that the Au/CeO2 catalyst prepared by DP method was the most efficient catalyst towards the total oxidation of toluene. The Au/CeO2 catalysts had obviously high catalytic activity, and the best results was obtained on 3 wt.% Au/CeO2 catalyst prepared by DP method. These catalysts were characterized by means of specific surface area (BET), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). XRD data showed that only metallic Au phase existed in the catalysts, and the size of gold particles played a crucial role in the catalytic conversion of toluene. The catalytic activity of Au/CeO2 was related to the interaction between gold particles and supports, and the capability of gold particles to weaken the surface Ce-O bonds adjacent to Au atoms. This interaction enhanced the reactivity of the CeO2 surface capping oxygen which was involved in volatile organic compounds oxidation.