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  1. No Access

    Article

    Effect of alloy composition on dispersion stability and catalytic activity for NO oxidation over alumina-supported Pt–Pd catalysts

    Applying a synthesis procedure that promotes alloy formation, highly-dispersed alumina-supported Pt–Pd catalysts spanning the Pt-rich half of the composition range were prepared, aged under oxygen-rich hydroth...

    G. W. Graham, H.-W. Jen, O. Ezekoye, R. J. Kudla, W. Chun, X. Q. Pan… in Catalysis Letters (2007)

  2. No Access

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    Promotion of the NO + O2 Reaction by Ba–Y, FAU Zeolite at 25 °C

    A remarkably high inferred initial rate of NO oxidation by O2 has been observed over Ba–Y, FAU zeolite at 25 °C in simple flow-reactor experiments. The rate of reaction at steady state was found to be lower, but ...

    H.-W. Jen, G. W. Graham in Catalysis Letters (2006)

  3. No Access

    Article

    Reducibility of Catalyzed Cerium–Praseodymium Mixed Oxides

    Cerium–praseodymium mixed oxides covering a wide range of cerium/praseodymium ratios were synthesized, loaded with 2 wt% palladium, and characterized by X-ray diffraction and temperature-programmed reduction. ...

    W. Chun, G. W. Graham, J. A. Lupescu, R. W. McCabe, M. M. Koranne… in Catalysis Letters (2006)

  4. No Access

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    Coarsening of Pt Particles in a Model NO x Trap

    The effects of temperature and atmosphere on the coarsening of Pt particles in a model NO x trap (Pt/BaO/Al2O3) were examined by XRD, TEM, and CO chemisorption. The main finding...

    G.W. Graham, H.-W. Jen, W. Chun, H.P. Sun, X.Q. Pan, R.W. McCabe in Catalysis Letters (2004)

  5. No Access

    Article

    Leaching of Ba2+ in NOx Traps

    It has been found that crystalline BaCO3 replaces crystalline BaAl2O4 in prototypical NO x traps upon exposure to liquid water. This phenomenon can be understood in terms of aci...

    G.W. Graham, H.-W. Jen, J.R. Theis, R.W. McCabe in Catalysis Letters (2004)

  6. No Access

    Article

    Revised Model of Strain in Ceria–Zirconia-Encapsulated Precious-Metal Particles

    A previously proposed model of strain in ceria–zirconia-encapsulated precious-metal particles is revised to reflect several new observations: encapsulation of unstrained Pt particles, quantitative relation bet...

    G.W. Graham, A.N. Shigapov in Catalysis Letters (2002)

  7. No Access

    Article

    Aging-Induced Metal Redistribution in Bimetallic Catalysts

    Alloy particles were detected by XRD in bimetallic catalysts, made from physical mixtures of powders comprising distinct metal-support combinations (e.g., Pd on alumina and Rh on ceria-zirconia), following hig...

    G.W. Graham, H. Sun, H.-W. Jen, X.Q. Pan, R.W. McCabe in Catalysis Letters (2002)

  8. No Access

    Article

    Observation of Strained PdO in an Aged Pd/Ceria-Zirconia Catalyst

    A model automotive-exhaust catalyst, Pd on Zr-rich ceria–zirconia, was characterized by X-ray diffraction, optical and electron microscopies, and micro-Raman spectroscopy following high-temperature aging. A br...

    G.W. Graham, A.E. O'Neill, D. Uy, W.H. Weber, H. Sun, X.Q. Pan in Catalysis Letters (2002)

  9. No Access

    Article

    Pd oxidation under UHV in a model Pd/ceria–zirconia catalyst

    A model planar catalyst was prepared by depositing Pd onto a thick (few μm) film of ceria–zirconia in ultrahigh vacuum (UHV), and the oxidation state of Pd and its support was determined by X-ray photoelectron...

    M.Yu. Smirnov, G.W. Graham in Catalysis Letters (2001)

  10. No Access

    Article

    UV Raman spectroscopy of adsorbed SOx on γ-alumina and Pt/γ-alumina catalysts

    Raman spectra of SOx adsorbed on γ-alumina and Pt/γ-alumina model catalysts have been obtained with a 244 nm Raman spectrometer. Strong peaks in the 980–1380 cm-1 region characteristic of adsorbed sulfates are cl...

    D. Uy, A. Dubkov, G.W. Graham, W.H. Weber in Catalysis Letters (2000)

  11. No Access

    Article

    Characterization of model automotive exhaust catalysts: Pd on Zr‐rich ceria–zirconia supports

    Model Pd automotive three‐way catalysts were prepared with high‐surface‐area Zr‐rich ceria–zirconia powders as support materials, aged for 12 h at 1050°C under redox conditions simulating automotive exhaust ga...

    G.W. Graham, H.‐W. Jen, R.W. McCabe, A.M. Straccia, L.P. Haack in Catalysis Letters (2000)

  12. No Access

    Article

    Ellipsometric study of a palladium catalyst during the oxidation of carbon monoxide and methane

    Spectroscopic ellipsometry is used to monitor the surface of a thick Pd‐film catalyst during the oxidation of either carbon monoxide or methane. Dense PdO layers form under sufficiently lean conditions (excess...

    G.W. Graham, D. König, B.D. Poindexter, J.T. Remillard, W.H. Weber in Topics in Catalysis (1999)

  13. No Access

    Article

    An examination of praseodymia as an oxygen‐storage component in three‐way catalysts

    The redox properties of praseodymia have been compared to those of ceria using temperature‐programmed desorption (TPD) of O2 from films prepared by vapor deposition onto an α‐Al2O3(0001) support, in order to asse...

    E.S. Putna, J.M. Vohs, R.J. Gorte, G.W. Graham in Catalysis Letters (1998)

  14. No Access

    Article

    Microstructure of a Pd/ceria–zirconia catalyst after high-temperature aging

    A model automotive exhaust catalyst, consisting of 2.25 wt% Pd supported on initially high-surface-area (88 m2/g) cerium–zirconium mixed oxide (Ce0.5Zr0.5O2), was studied by X-ray diffraction (XRD), thermogravime...

    J.C. Jiang, X.Q. Pan, G.W. Graham, R.W. McCabe, J. Schwank in Catalysis Letters (1998)

  15. No Access

    Article

    Sol-Gel Precursors and the Oxygen Storage Capacity of PrOy-ZrO2 Materials

    The gels derived from mixtures of Pr(OiC3H7)3 and Zr(OiC3H7)4⋅iC3H7OH, upon hydrolysis and pyrolysis, furnish single-phase PrOy-ZrO2 materials crystallized in the fluorite structure. These materials can be coated...

    C. K. Narula, K. L. Taylor, L. P. Haack, L. F. Allard… in MRS Online Proceedings Library (1997)

  16. No Access

    Article

    Encapsulation of Pd particles by ceria-zirconia mixed oxides

    Redox aging above 1000°C of initially high-surface-area (of order 100 m2/g) cerium-rich ceria-zirconia mixed oxides containing a few wt% Pd results in the loss of most of the surface area and concomitant encapsul...

    G.W. Graham, H.-W. Jen, W. Chun, R.W. McCabe in Catalysis Letters (1997)

  17. Article

    An experimental process improvement study of nonODC degreasers in high stability strain gage installations

    G. W. Graham, G. A. Vellutini, C. P. Wright in Experimental Techniques (1997)

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  18. No Access

    Article

    Kinetic and structural studies of oxygen availability of the mixed oxides Pr1–xMxOy (M = Ce, Zr)

    One composition of Pr–Ce mixed oxide and a range of compositions of Pr–Zr mixed oxide were prepared by coprecipitation methods and characterized by x-ray powder diffraction, thermogravimetric analysis, and x-r...

    M. Yu. Sinev, G. W. Graham, L. P. Haack, M. Shelef in Journal of Materials Research (1996)

  19. No Access

    Article

    Highly dispersed MgO-supported model Pd-Mo catalysts prepared from bimetallic clusters: Chemisorption and selective catalytic reduction of NO

    Model supported palladium and palladium-molybdenum catalysts prepared from organometallic precursors and previously characterized by a variety of chemical and physical methods were examined by IR spectroscopy ...

    T. E. Hoost, G. W. Graham, M. Shelef, O. Alexeev, B. C. Gates in Catalysis Letters (1996)

  20. No Access

    Article

    In situ ellipsometric study of a palladium catalyst during the oxidation of methane

    Ellipsometry is used to follow the growth of a PdO layer on the surface of a thick Pd-film catalyst during methane oxidation at ∼ 500°C. The oxide layer that develops under rich conditions (excess CH4) is quite p...

    D. König, W. H. Weber, B. D. Poindexter, J. R. McBride, G. W. Graham… in Catalysis Letters (1994)

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