Tuning the metal-support interaction in the thermal-resistant Au–CeO2 catalysts for CO oxidation: influence of a mild N2 pretreatment

Abstract

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 N₂ has been reported to re-activate the Au–CeO₂ catalysts that were prepared by a deposition–precipitation method followed by calcination at 600 °C. Upon N₂ pretreatment at 200 °C, the metal-support interaction between Au nanoparticles (NPs) and CeO₂ was observed with the evidence of particular coverage of Au nanoparticles by CeO₂, electronic interactions and changes in CO adsorption ability. As a result, the CO oxidation activity of the pretreated Au–CeO₂ catalysts largely improved compared with those without any pretreatment and even with those subjected to H₂ and O₂ pretreatments. N₂ 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.