Nano-Sized Au/CeO2 Catalysts for Total and Selective CO Oxidation
Au/CeO2 catalysts prepared by a deposition-precipitation and a co-precipitation method were applied to CO oxidation in the absence and presence of hydrogen. The transmission electron microscope (TEM), the temperature programmed reduction (TPR), and the X-ray absorption near edge structure (XANES) were conducted to probe structural and electronic properties of gold. Au2O3 was determined to be mainly present when Au/CeO2 was prepared by a deposition-precipitation method. However, the metallic gold was observed in a co-precipitated Au/CeO2 catalyst. Au/CeO2 containing oxidized gold species, prepared by a deposition-precipitation method, showed the decreasing CO conversion with a reaction time, which accompanied the reduction of gold from Au(+3) to Au(0). However, co-precipitated Au/CeO2 showed the stable CO conversion. The effect of pretreatment condition on CO oxidation was also examined. These results support that Au/CeO2 catalyst containing oxidized gold species was superior to Au/CeO2 catalyst containing the metallic gold for CO oxidation. This Au/CeO2 catalyst was also active for the selective CO oxidation in the presence of hydrogen.
Byung Tae Ahn, Hyeongtag Jeon, Bo Young Hur, Kibae Kim and Jong Wan Park
E. Y. Ko et al., "Nano-Sized Au/CeO2 Catalysts for Total and Selective CO Oxidation", Solid State Phenomena, Vols. 124-126, pp. 1749-1752, 2007