Ultrasonic-assisted synthesis of highly active catalyst Au/MnOx–CeO2 used for the preferential oxidation of CO in H2-rich stream

Abstract A series of nano-gold catalysts supported on binary oxides MO x –CeO 2 (atomic ratio M/Ce = 1:1, M = Mn, Fe, Co, Ni) are prepared by deposition–precipitation (DP). An innovative and rather convenient ultrasonic pretreatment of the support is employed for Au/MnO x –CeO 2 preparation. It is found that for preferential CO oxidation Au/MnO x –CeO 2 is more active than Au/CeO 2 . Ultrasonic pretreatment of MnO x –CeO 2 further promotes the performance of Au/MnO x –CeO 2 , with CO conversion increased by 24 % at 120 °C. Meanwhile, the selectivity of oxygen to CO 2 is promoted in the whole temperature range, especially in 80–120 °C, the selectivity is increased by 15–21%. HR-TEM and XRD results indicate that ultrasonic pretreatment is favorable to the formation of much smaller gold nanoparticles ( 2 -TPR and CO-TPR confirms that the strong interaction between Au and the support effectively inhibits the dissociation and oxidation of H 2 over the ultrasonically pretreated catalyst Au/MnO x –CeO 2 , making it highly selective to CO oxidation.