Papers by Author: D. Yang

Abstract: A number of experiments were carried out with different Ce-Zr oxides doped La3+、Pr3+ or Mn4+ in order to improve their performance as a promoter for three way catalyst(TWC). The XRD results showed that the thermal stability of Ce-Zr oxide doped lanthanum or praseodymium was improved, especially at high temperature. H2-TPR test detected the low –temperature redox behavior of Ce-Zr oxide was promoted strongly attributed to the MnO2, with calcined temperature increasing, the reduction peaks were moved to high temperature for Ce-Zr oxide doped La3+ and Pr3+. The catalytic activity of Ce-Zr oxide doped Mn4+ was also enhanced, the light-off temperature was lower 10K than Ce-Zr oxide; the conversions of CO and THC were higher 3-4% than Ce-Zr oxide.

Abstract: Herein mesoporous CeO2 with high thermal stability was synthesized via a new hydroxycarbonates based hydrothermal threatment approach in present of hexadecyltrimethylammonium bromide (CTAB). IR and XRD prove the coexistence of hydroxycarbonate cerium and CTAB in precursors. TEM micrographs show that non-ordered pore structure is formed in the product, and average particle size of 20 nm is obtained even after calcined at 1173 K. BET results exhibit that the pore structure is stable when the calcination temperature is below 923 K. However, While calcinated at 1173 K, the average particle size is 20 nm, the BET surface area and pore volume can remain as high as 31.07 m2/g and 0.21 cm3 g-1.

Abstract: The traditional precipitation method and a novel inorganic-organic hybrid method were used to control the morphology of nanocrystalline CeO2. By adjusting the methods and the preparation conditions, spherical and rode-shaped cerium dioxides with the nanoparticle sizes were prepared. Their structures and properties were characterized by XRD, BET and TEM.