10.
Ceria-supported Au catalyst has been synthesized by the solution combustion method for the first time and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Au is dispersed as Au
0 as well as Au
3+ states on CeO
2 surface of 20-30 nm crystallites. On heating the as-prepared 1% Au/CeO
2 in air, the concentration of Au
3+ ions on CeO
2 increases at the expense of Au
0. Catalytic activities for CO and hydrocarbon oxidation and NO reduction over the as-prepared and the heat-treated 1% Au/CeO
2 have been carried out using a temperature-programmed reaction technique in a packed bed tubular reactor. The results are compared with nano-sized Au metal particles dispersed on -Al
2O
2 substrate prepared by the same method. All the reactions over heat-treated Au/CeO
2 occur at lower temperature in comparison with the as-prepared Au/CeO
2 and Au/Al
2O
2. The rate of NO + CO reaction over as-prepared and heat-treated 1% Au/CeO
2 are 28.3 and 54.0 mol g
-1 s
-1 at 250 and 300 °C respectively. Activation energy (
E
a) values are 106 and 90 kJ mol
-1 for CO + O
2 reaction respectively over as-prepared and heat-treated 1% Au/CeO
2 respectively.
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