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Showing papers in "Journal of Catalysis in 1998"


Journal ArticleDOI
TL;DR: In this article, it was shown that propylene adsorbed on a gold surface may react with oxygen species formed at the perimeter interface between the gold particles and the TiO2support through the reaction of oxygen with hydrogen.

1,076 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of composition and surface and catalytic properties of Mg-Al mixed oxides was studied by combining several characterization methods with ethanol conversion reactions, and the nature, density, and strength of surface basic sites depended on the Al content.

1,029 citations


Journal ArticleDOI
TL;DR: In this article, gold-based catalysts have been used for catalytic diol conversion to α-hydroxy carboxylates with dioxygen in an alkaline solution.

542 citations


Journal ArticleDOI
TL;DR: In this paper, a Mars-van Krevelen redox mechanism involving the activation of methane on site pairs consisting of oxygen atoms and oxygen vacancies on the surface of PdOxcrystallites was investigated.

454 citations


Journal ArticleDOI
TL;DR: In this paper, high surface area molybdenum and tungsten carbide materials, synthesised by the temperature programming reduction of the relevant metal oxide with methane/hydrogen, are highly efficient catalysts for the conversion of methane to synthesis gas, via the steam reforming, dry reforming, or partial oxidation processes.

360 citations


Journal ArticleDOI
TL;DR: In this article, aqueous ion exchange with H-ZSM5 (Si/Al=14.5) leads to isolated Zn2+cations with tetrahedral symmetry.

357 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that only 0.3% of the chromium is leached during the reaction, which corresponds to a substrate/Cr ratio of 17.000.

325 citations


Journal ArticleDOI
TL;DR: In this article, the condensation of benzaldehyde and acetone to aldol has been investigated in the liquid phase at 273 K on hydrotalcites transformed into basic solids by activation following different procedures.

319 citations


Journal ArticleDOI
TL;DR: The gas-solid reaction between methane and cerium oxide (CeO2) directly produced a synthesis gas with H2/CO ratio of 2.1±0.1.

307 citations


Journal ArticleDOI
TL;DR: In this paper, the performances of two very active catalysts for VOC removal (one metal oxide and one noble metal catalyst, namely gamma-MnO2 and Pt/TiO2) are compared, taking into account not only the activity but also the sensitivity to competition effects between compounds, the influence of water vapor and the stability.

304 citations


Journal ArticleDOI
TL;DR: In this article, the kinetics of CO2reforming of CH4 were studied over Pt supported on TiO2, ZrO2 and Cr2O3, and the catalysts were characterized using chemisorption, X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), temperature-programmed hydrogenation (TPH), and temperatureprogrammed surface reaction.

Journal ArticleDOI
TL;DR: Glycerolysis of triolein and rapeseed oil were carried out with base catalysts such as Cs-MCM-41, Cs -Sepiolite, MgO, and calcined hydrotalcites with different Al/Al+Mg ratios as mentioned in this paper.

Journal ArticleDOI
TL;DR: The structure of vanadia species supported on zirconia depends on VO{sub x} surface density and on the temperature of catalyst oxidation pretreatments as mentioned in this paper, and vanadium surface density increases with increasing surface density.

Journal ArticleDOI
TL;DR: In this paper, the conversion of methane to benzene in the absence of oxygen has been investigated over different TMI/H-ZSM-5 zeolites (with TMI=Mo, Fe, V, W, and Cr) as a function of preparation and treatment method, the metal ion loading, and the zeolite acidity.

Journal ArticleDOI
TL;DR: In this article, the catalytic activity of nanocrystalline doped ceria and Cu-and Ag-modified ceria for the complete oxidation of methane was studied by X-ray diffraction and related to the availability of low-temperature oxygen species.

Journal ArticleDOI
TL;DR: Despite the high thermodynamic driving force to form coke under the reaction conditions applied Pt/ZrO2 and Rh supported on γ-Al2O3 and ZrO 2 are active and stable catalysts for CO2/CH4reforming using steady state, transient kinetic measurements and physico-chemical characterization techniques.

Journal ArticleDOI
TL;DR: In this article, transient, isothermal photocatalytic oxidation (PCO) was combined with isotope labeling and temperature-programmed desorption and oxidation to directly identify reaction pathways and intermediates for the room temperature PCO of ethanol on TiO2.

Journal ArticleDOI
TL;DR: Titania and titania modified with 3 and 12 mu mol Ce/m(2) surface area of the titania were prepared and were used as supports for copper oxide as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, the authors showed that a partial blockage of the monodimensional pores of MCM-41, which decreased the accessibility of the reactants to the Bronsted acid sites of the heteropolyacid located inside the pores, can be decreased, and the catalytic activity of HPW/MCM41 catalysts increased, by using a sample with larger pore diameter.

Journal ArticleDOI
TL;DR: The synthesis, characterization, and proposed formation mechanism of mesoporous high surface area ceria is described in this paper, where it is shown that the reaction of cerium salts under basic conditions with ammonia in the presence of a cationic surfactant results in the precipitation of a gelatinous hydrous cerium oxide/surfactant mixture, which after drying and calcination gives pure, high surface-area, fluorite-structured CeO2.

Journal ArticleDOI
TL;DR: In this paper, a combination of CO adsorption at 300 K, which provides irreversible adsorbing on Cu+1 sites, and oxygen adsorment via N2O dissociation at 363 K, counts surface Cu0atoms, was used to obtain values for the dispersion of Cu on SiO2, Al2O3, TiO2 and diamond powder, and graphitized carbon fibers.

Journal ArticleDOI
TL;DR: In this article, isothermal and temperature-programmed oxidation and reduction were used to study the dynamics of Pd oxide and the structure of the oxide formed as well as PdO reduction by H 2 and CH 4.

Journal ArticleDOI
TL;DR: In this article, the influence of (hydro)thermal treatments on the catalytic activity of zeolite Beta in the Lewis acid-catalyzed Meerwein-Ponndorf-Verley reduction of ketones was investigated.

Journal ArticleDOI
TL;DR: In this article, the authors used ammonium carbonate and nitric acid washing solutions to extract uncombined copper oxide and showed that ammonium-carbonate was only effective for removing dispersed CuO, whereas nitric acids removed both dispersed and crystalline CuO. The results indicated that the active sites are copper species derived from CuAl2O4 and CuCr2O 4 spinels rather than from CuO and indicated that Cu species in tetrahedral coordination lead to higher activity.

Journal ArticleDOI
TL;DR: In this article, a large number of oxide-based systems have been investigated, and effective OCM catalysts may be broadly classified into irreducible metal oxides, rare earth oxides and reducible metal oxide.

Journal ArticleDOI
TL;DR: In this paper, the binding energy of Pd 3d5/2core level spectrum of catalyst 1% Pd/ZnO prereduced at temperatures as low as 373 K and catalyst 5% pd/znO reduced at 573 K and above.

Journal ArticleDOI
TL;DR: The chromium oxide-alumina catalysts of the Cr loading varying between 1 and 50 Cr nm −2 have been characterized by different physicochemical techniques and probe reactions of acid-basic properties and of the catalyst oxygen reactivity.

Journal ArticleDOI
TL;DR: The catalytic combustion of CH4 has been investigated over Pd/ZrO2 with the aim of identifying how the state of oxidation of the Pd affects the catalytic activity, particularly at low temperatures as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, the use of a large probe molecule like di-tert-butyl-pyridine (DTBPy) is showed to be adequate to characterize the acid sites located at the external surface of zeolites.

Journal ArticleDOI
TL;DR: In this article, the reduction rate of NO{sub x} to N{sub 2} was investigated over Fe/ZSM-5 with the presence of nitrogen-containing deposits on the catalyst.