A series of nanopowder Ce–Zr–Pr oxide catalysts were synthesized by a new method which was a low temperature synthesis approach combining rotating evaporation and auto-combustion techniques. The catalysts were characterized by means of XRD, Raman, and SEM. The results showed that the synthesized catalysts had a cubic fluorite structure, nanoparticle sizes and good catalytic activity for soot oxidation.

The La1-xKxMnO3 perovskite-type oxides whose sizes were in nanometric range were prepared by the citric acid-ligated method. The structures of these perovskite-type oxides were examined by XRD and FT-IR. The catalytic activity for the combustion of soot particulate was evaluated by a technique of the temperature-programmed reaction. In the LaMnO3 catalyst, the partial substitution of K for La at A-site enhanced the catalytic activity for the combustion of soot particle. In the La1-xKxMnO3 catalysts, the combustion temperature of soot particle decreases with increasing x values. The La1-xKxMnO3 oxides with the substitution quantity between x=0.20 and x=0.25 are good candidate catalysts for the soot particle removal reaction, and the combustion temperature of soot particle is between 285 and 430℃ when the contact of catalysts and soot is loose, and their catalytic activities for the combustion of soot particle are as good as supported Pt catalysts, which is the best catalyst system so far reported for soot combustion under loose contact conditions.

Selective oxidation of ethane by oxygen was examined over silica catalysts supporting cesium and bismuth. Aldehydes of C1–C3 were obtained with total selectivity of about 40% at ethane conversion lower than 5%. The catalytic performance was strongly dependent upon the bismuth loading on the catalysts. The higher turn-over-rate and the higher selectivity to aldehydes were observed at the Bi loadings lower than 0.5%. Characterization of the catalysts showed that isolated or highly dispersed Bi on the catalyst surface was indispensable for the high aldehyde yield. Cesium also plays an important role for the high ethane reactivity and the high aldehyde selectivity. A reaction pathway was proposed in which ethane is oxidized into acetaldehyde, but not through ethylene, and acrolein is formed through a cross-condensation of acetaldehyde and formaldehyde.

Bulk V-Nb-O, Mo-Nb-O, Te-Nb-O, and V-Mo-Te-Nb-O mixed metal oxides were synthesized and characterized with Raman spectroscopy, XRD, and BET methods. The interaction of the V and Mo cations with the Nb2O5 lattice followed three stages: (1) cations were initially incorporated into the Nb2O5 lattice forming a solid solution or compound as well as on the Nb2O5 surface, (2) a two-dimensional surface cation overlayer was formed after saturation of the solid solution, and (3) microcrystalline metal oxide phases (e.g., V2O5 and MoO3) were formed after completion of the two-dimensional surface cation monolayer. The catalytic properties of these bulk mixed metal oxides were investigated for the oxidative dehydrogenation (ODH) of propane to propylene, and their activity follows the trend: V-Nb-O > Mo-Nb-O>>Nb2O5 > Te-Nb-O. The highest propane conversions and propylene yields were found when the two-dimensional surface metal oxide monolayers were formed, which suggests that the surface metal oxide species are the surface active sites in these bulk mixed metal oxide catalysts for propane ODH. Furthermore, the number of surface active sites present in the bulk mixed metal oxides was determined by comparative studies between the bulk mixed metal oxides and the corresponding model Nb2O5-supported metal oxides. These numbers can be used further for the calculation of the TOF (turn-over-frequency) values and quantitative comparison of the catalytic behavior of the different bulk mixed metal oxide catalysts for propane ODH. The catalytic results over the model Nb2O5-supported metal oxides demonstrate that the propane ODH reaction is structure insensitive because the TOF is independent of the number and the structure of surface active sites. The composition and calcination temperature of the bulk mixed metal oxide catalysts affects the surface density of the active sites, which controls their catalytic behavior for propane ODH.

SBA-15 silica-supported potassium catalysts were first reported for the selective oxidation of ethane to aldehydes by using oxygen as oxidant. It was found that SBA-15-supported potassium catalysts exhibited very high yield of aldehydes, especially surprisingly high yield of acrolein in the selective oxidation of ethane. The SBA-15-supported catalyst with 2% loading of potassium showed the best performance for the partial oxidation of ethane to aldehydes. The yields highest of acrolein and total aldehydes (formaldehyde, acetaldehyde, and acrolein) were 2.5% and 5.2%, respectively, when the ethane conversion was 14.8% at the reaction temperature of 748 K.