Determination of the dispersion of supported Pt particles by gas-phase and liquid-phase measurements

Kivrak, Hilal
Mastalir, Agnes
Kiraly, Zoltan
Üner, Deniz
The dispersion of a Pt/gamma-Al2O3 catalyst was investigated by various experimental techniques. The values obtained by gas-phase hydrogen and carbon monoxide adsorption and transmission electron microscopy (TEM) were consistent for the metal:adsorbate stoichiometry of 1:1. However, these methods overestimated the number of active sites available for a liquid-phase reaction. For the hydrogenation of styrene in the presence Of CS2 as a catalyst poison, only the defect sites were found to be active in the catalytic reaction. The defect sites were related to the initial coverage dependent region of the adsorption heats measured by gas-phase microcalorimetry.


CABBAR, C; DOGU, G; Doğu, Timur; MCCOY, BJ; SMITH, JM (American Chemical Society (ACS), 1994-07-01)
The single-pellet moment technique was shown to be a powerful method for investigating the diffusion and adsorption of volatile hydrocarbons in the soil. The technique was used to evaluate effective diffusivities, adsorption equilibrium, and rate constants of chlorinated hydrocarbons (monochloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane). Results obtained in a dry system showed that adsorption rate constants of all these hydrocarbons on the soil pellet used are of the same ...
The role of alkali-metal promotion on CO oxidation over PdO/SnO2 catalysts
MİRKELAMOĞLU, BURCU; Karakaş, Gürkan (Elsevier BV, 2006-01-17)
Sol-gel prepared PdO/SnO2 and Na-PdO/SnO2 catalysts were investigated by X-ray photoelectron spectroscopy (XPS), diffuse reflectance IR (DRIFTS), temperature-programmed reaction spectroscopy (TPRS) and impulse techniques. Alkali-metal promotion was observed to enhance CO oxidation rate and decreases light-off temperatures of PdO/SnO, XPS analysis revealed that alkali-metal promotion resulted in the segregation of Pd atoms and promoted the oxygen storage capacity of the catalysts. The presence of super-oxide...
In situ DRIFTS characterization of wet-impregnated and sol-gel Pd/TiO 2 for NO reduction with CH4
Karakaş, Gürkan; Ozkan, Umit S. (Elsevier BV, 2002-05-01)
The adsorption/desorption behavior of 2%Pd/TiO2 catalysts synthesized by wet-impregnation and modified sol–gel techniques were examined in NO–CH4–O2 reaction using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The catalyst prepared by the modified sol–gel method showed significantly higher resistance toward oxygen while maintaining a 100% NO conversion. Under NO+CH4+O2 flow, the main adsorbed NO species was identified as the linearly adsorbed NO on metallic palladium (Pd0–NO)...
Effect of hydrogen ion-exchange capacity on activity of resin catalysts in tert-amyl-ethyl-ether synthesis
Boz, N; Doğu, Timur; Murtezaoglu, K; Dogu, G (Elsevier BV, 2004-08-10)
Activities of ion-exchange resin catalysts, having different hydrogen exchange capacities ranging between 5.1 and 1.3 meq H+/g, on the etherification reactions of 2M1B (2-methyl-1-butene) and 2M2B (2-methyl-2-butene) with ethanol were experimentally tested in a fixed bed reactor. These catalysts were prepared by the heat treatment of Amberlyst-15 catalysts at 220 degreesC at different durations of time and also by the synthesis of sulfonated styrene divinyl benzene cross-linked resins. Activity of these cat...
Coke Minimization in Dry Reforming of Methane by Ni Based Mesoporous Alumina Catalysts Synthesized Following Different Routes: Effects of W and Mg
ARBAĞ, HÜSEYİN; YAŞYERLİ, SENA; YAŞYERLİ, NAİL; Doğu, Timur; DOĞU, GÜLŞEN (Springer Science and Business Media LLC, 2013-12-01)
Ni based mesoporous alumina (MA) catalysts were synthesized by sol-gel (SGA) and hydrothermal (MA) methods, following impregnation and one-pot synthesis routes and catalytic performances of these materials were tested in dry reforming of methane. Results proved the importance of synthesis procedure of the MA supports on the activity and coke resistance of the synthesized materials, containing 16 % Ni. Among these catalysts, MA prepared by the sol-gel technique (Ni@SGA) showed the highest activity in dry ref...
Citation Formats
H. Kivrak, A. Mastalir, Z. Kiraly, and D. Üner, “Determination of the dispersion of supported Pt particles by gas-phase and liquid-phase measurements,” CATALYSIS COMMUNICATIONS, pp. 1002–1005, 2009, Accessed: 00, 2020. [Online]. Available: