Al_2O_3 supported Ru catalysts prepared by thermolysis of Ru_3(CO)_(12) for catalytic wet air oxidation

摘要

Low loading catalysts Ru/γ-Al_2O_3 and Ru-Ce/7-Al_2O_3 were prepared by thermolysis of Ru_3(CO)_(12) on γ-Al_2O_3. The catalysts were characterized by XPS, XRD and SEM. Two new Ru species (Ru_A and Rub) were detected during the Ru_3(CO)]_2 decomposition process due to chemical interaction with the active OH groups on the surface of Al_2O_3 support, and the reduction of them can lead to more dispersed metal- lic phases. The sample was completely decomposed at 673 K in H_2, and RuO_2 was formed with minor amounts of Ru~0. When the temperature was increased to 773 K to heat the sample, the ratio of Ru~0to RuO_2 increased. However, after the addition of CeO_2, only RuO_2 was detected on surface. The catalysts exhibited high activities in Catalytic Wet Air Oxidation (CWAO) of different organic compounds at high concentration such as isopropyl alcohol, phenol, acetic acids and N,N-dimethylformamide, which is attributed to the better dispersion of Ru particles and the addition of CeO_2 further enhanced number of effectively active sites on the cluster-derived catalyst surface.