clay and ceric-oxide

A series of Fe/CeO2-intercalated clay catalysts were synthesized successfully, the physicochemical properties of the catalysts were characterized by XRD, BET, XRF, TG, FT-IR, O2-TPD, H2-TPR and XPS methods. The catalytic performances for selective catalytic oxidation of H2S were further investigated, all catalysts exhibited high catalytic activities. Among them 5% Fe/Ce-Lap presented the best activity at 180 degreeC and the maximum sulfur yield was up to 96% due to the interaction between iron and cerium, which improved the redox ability of Fe3+ . Moreover, the strong oxygen adsorption capacity and the well dispersion of iron species improved the catalytic performance efficiently.

Topics: Adsorption; Aluminum Silicates; Catalysis; Cerium; Clay; Hydrogen Sulfide; Intercalating Agents; Iron; Oxidation-Reduction; Silicates

Laponite clays composited with alumina, ceria and zirconia etc. were prepared using polyoxocations or simple metal ions as precursors, and then cobalt oxide was loaded onto them to obtain the catalysts. The results showed that compared with laponite clays, the as-prepared laponite had wide range of pore size distribution and increased pore volume. The pore volumes of laponite clays composited with alumina and ceria were more than 0.75 cm3 · g(-1). N2 isotherm type was maintained after Co3O4 loading, however, the N2 adsorption decreased with the increase of Co3 O4 loading, indicating the decrease of pore volume, which was caused by the blockage of metallic oxide/clay composites support. Furthermore, dispersion and catalytic performance of the catalysts were significantly influenced by the composited metallic elements. It was shown that according to the diffraction peak half-width of 311 crystal facet and scherrer equation, when the Co loading was 21.3% at laponite clays composited with Fe, Zr, Ce, Al, the average sizes of Co3O4 were 17.2, 16.0, 16.5 and 18.0 nm, respectively. Alumina composited clay with 21.3% Co loading showed high catalytic activity, the complete conversion temperature of benzene was 350°C. Among metallic oxide/laponite composites, the ZrO composited laponite with 21.3% Co loading exhibited the best catalytic performance, which could completely convert benzene at 310°C.

Topics: Adsorption; Aluminum Oxide; Aluminum Silicates; Benzene; Catalysis; Cerium; Clay; Cobalt; Hot Temperature; Oxidation-Reduction; Oxides; Silicates; X-Ray Diffraction; Zirconium

New pillared clay catalysts were studied for NO removal by hydrocarbon in the presence of oxygen. The purpose of this work is to study the deactivation of Cu/Al-Ce-PILC in the SCR of NO. Montmorillonite was pillared by multi oligomeric hydroxyl cation to synthesize Al-Ce-PILC and treated by (NH4) 2SO4, then it was used as catalyst support. Cu/Al-Ce-PILC catalyst was prepared by impregnation and applied to the SCR of NO by C3 H6. The NO conversion to N2 reached its maximum of 56% at 350 degrees C and decreased to 22% at 700 degrees C. To study the deactivation of Cu/Al-Ce-PILC in the SCR of NO at high temperature, the fresh and post-reaction catalysts were characterized by XPS, TPR, TGA, Py-IR and DSC. The results showed that only Cu+ species existed on the fresh catalyst pretreated in hydrogen, while another species CuO was detected on the post-reaction catalyst. The loss of structural hydroxyl and SO4(2-) on Al-Ce-PILC weakened the surface acidity of the catalyst at high reaction temperature. Furthermore, the coke deposition on the catalyst covered part of the active sites and blocked the pores of the catalyst. The deactivation of Cu/Al-Ce-PILC may be due to the combined effects of CuO formation, the decrease on acidity and the coke deposition, which facilitated propylene combustion and inhibited NO reduction.

Topics: Alkenes; Aluminum Oxide; Aluminum Silicates; Catalysis; Cerium; Clay; Copper; Nitric Oxide; Oxidation-Reduction