Being endowed with an ability of capturing and releasing oxygen, the ceria surface conventionally assumes the role of catalyzing redox reactions in chemistry. This catalytic effect also makes possible its cytotoxicity toward microorganisms at room temperature. To study this cytotoxicity, we synthesized the doped and undoped ceria particles of 8-9 nm in size using an inexpensive precipitation me...

In recent years, ceria and doped-ceria anisotropic nanocrystals (NC’s) have been produced by a variety of solution-based synthetic routes. The motivation in producing ceria-based NCs with controlled morphology is to develop high surface area catalyst supports with well-defined exposed crystal planes that exhibit optimal catalytic activity. Understanding the growth mechanism of CeO2 NC’s is vita...

A quasi in situ X-ray absorption study demonstrated that the disproportionation of hydrogen peroxide (H2O2) promoted by ceria nanorods was associated with a reversible Ce(3+)/Ce(4+) reaction and structural transformations in ceria. The direction of this reversible reaction was postulated to depend on the H2O2 concentration and the fraction of Ce(3+) species in ceria nanorods.

A significant morphology change from ceria nanoparticles to nanocubes was observed in ceria nanocrystals when CO molecules were introduced into the synthetic system, which is attributed to the surface selective growth driven by strong surface selective adsorption of CO onto the ceria surface.

The effect of the suppport on oxidative dehydrogenation activity for vanadia/ceria systems is examined for the oxidation of methanol to formaldehyde by use of well-defined VO(x)/CeO(2)(111) model catalysts. Temperature-programmed desorption at low vanadia loadings revealed reactivity at much lower temperature (370 K) as compared to pure ceria and vanadia on inert supports such as silica. Densit...

The mechanism responsible for the irreversible deactivation of ceria-supported precious metals for the watergas-shift reaction has been investigated through accelerated aging tests. It is shown that deactivation of Pd/ ceria occurs more rapidly at 673 K compared to 523 K when operating with an integral reactor in 25 torr each of CO and H2O. By heating a fresh catalyst in H2, H2O, CO, or CO2, it...

The growth morphology and structure of ceria nano-islands on a stepped Au(788) surface has been investigated by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). Within the concept of physical vapor deposition, different kinetic routes have been employed to design ceria-Au inverse model catalysts with different ceria nanoparticle shapes and arrangements. A two-dime...

Nanostructured Au–ceria is a promising new catalyst for low-temperature water-gas shift (LTS). Preparation, characterization, and catalytic properties of this material are reported in this paper. Gold–ceria was prepared by deposition–precipitation (DP), coprecipitation (CP), and gelation methods. The gold loading was varied between 1 and 8.3 at.%, while lanthanum used as a dopant in ceria, was ...

Interactions between ceria (CeO2) and supported metals greatly enhance rates for a number of important reactions. However, direct relationships between structure and function in these catalysts have been difficult to extract because the samples studied either were heterogeneous or were model systems dissimilar to working catalysts. We report rate measurements on samples in which the length of t...

The catalyst Pt(1 wt %)/Ce(0.6)Zr(0.4)O(2) is studied by CO-temperature programmed reduction (CO-TPR), isothermal oxygen storage complete capacity (OSCC), X-ray absorption spectroscopy (XAS) at the Pt L(III) edge, and in situ X-ray diffraction (in situ XRD), with the aim of elucidating the role of supported metal in CO oxidation by ceria-based three-way catalysts (TWC). The redox behavior of Pt...