Tuning the metal-support interaction in the thermal-resistant Au-CeO 2 catalysts for CO oxidation: influence of a mild N 2 pretreatment.

Pretreatment is very important for altering the catalytic properties of the supported noble metal catalysts in many heterogeneous reactions. In this study, a simple and mild pretreatment with N 2 has been reported to re-activate the Au-CeO 2 catalysts that were prepared by a deposition-precipitation method followed by calcination at 600 °C. Upon N 2 pretreatment at 200 °C, the metal-support interaction between Au nanoparticles (NPs) and CeO 2 was observed with the evidence of particular coverage of Au nanoparticles by CeO 2 , electronic interactions and changes in CO adsorption ability. As a result, the CO oxidation activity of the pretreated Au-CeO 2 catalysts largely improved compared with those without any pretreatment and even with those subjected to H 2 and O 2 pretreatments. N 2 pretreatment also makes the Au NPs more resistant to sintering at high temperature. Furthermore, this mild pretreatment strategy can provide a potential approach to improve the thermal stability of other supported noble metal catalysts.