| Popis: |
Hierarchically organized γ-Al2O3 hollow microspheres were prepared via a hydrothermal method using potassium aluminum sulfate and urea as reactants. The corresponding Au/Al2O3 catalysts were obtained using a deposition-precipitation (DP) method. The effect of the pretreatment under different atmospheres (N2, air, and H2) on the activity and stability of the Au/Al2O3 catalysts in CO oxidation was investigated. The results showed that the pretreatment under H2 atmosphere improved the low-temperature CO oxidation activity. Furthermore, a 50 h long-term test at 30 °C showed no significant deactivation for the H2-pretreated catalyst. Moreover, the catalytic activity was promoted by H2O vapor in all cases, and the H2-pretreated catalyst exhibited a good tolerance in the co-presence of CO2 and H2O. Finally, oxygen temperature-programmed desorption (O2-TPD) and in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) revealed that the reductive atmosphere pretreatment greatly improved the CO adsorption capacity and facilitated the oxygen activation. |
