Showing papers in "Journal of Catalysis in 1978"

TL;DR: In this paper, the authors discussed the need for a reducible, transition metal oxide support and on the basis of bonding mechanisms suggested by known compounds, showed that Iridium exhibits normal H2-chemisorption (typical of Ir Al 2 O 3 and Ir SiO 2 ) following reduction at 200 °C.

TL;DR: In this article, the authors studied the oxidation of methanol to formaldehyde by flash decomposition spectroscopy on a single crystal of a Cu(110) single crystal.

TL;DR: Mixed oxide catalysts, containing molybdenum and vanadium (MoV) together with another transition metal oxide (Ti, Cr, Mn, Fe, Co, Ni, Nb, Ta, or Ce), are active as low as 200 °C for the oxydehydrogenation of ethane to ethylene.

TL;DR: The influence of the Al content and cation type on physicochemical properties of aluminosilicates is explained using Sanderson's electronegativity scale as mentioned in this paper, which is used to explain the influence of Al contents and cations on aluminosity.

TL;DR: In this paper, a carbenium ion-based mechanism was proposed for the conversion of methanol and ethanol to branched aliphatics on a synthetic zeolite of the type H-ZSM-5.

TL;DR: In this article, it is suggested that these differences in catalytic performance may be related to the inability of Pd to chemisorb CO dissociatively at reaction temperatures, compared to other Group VIII metals.

TL;DR: The adsorption of CO on Ni at 300 °C is dissociative, resulting in disproportionation to CO2 and a NiC species as mentioned in this paper, and the adsorbed CO is inert to H2.

TL;DR: In this article, the interaction of cupric ions with γ-alumina supports was studied by physical characterization of a wide range of catalyst preparations, and the results from different techniques, including extended X-ray absorption fine structure (EXAFS), Xray absorption edge shifts, Xray diffraction, ESR, ESCA, and optical spectroscopy, were combined with prior work to develop a coherent description of the phases present and cation site distribution in the virgin and aged catalysts.

TL;DR: When used as a catalyst for conversion of synthesis gas at pressures above 25 atm, supported rhodium produces two-carbon oxygen-containing compounds, specifically acetic acid, acetaldehyde, and ethanol, with chemical efficiencies on the order of 50% as discussed by the authors.

TL;DR: In this paper, the authors investigated the hydrogenation of CO and CO 2 over polycrystalline iron foils under highly controlled conditions (6 atm, 3:1 H 2 :CO, 300 °C).

TL;DR: In this paper, the activation energies, kinetic orders, and relative activities have been determined for the oxidation of CO by O2 over five supported noble metals, including iridium, rhodium, and palladium.

TL;DR: The effect of catalyst support on the activity and product selectivity of CO hydrogenation by ruthenium is discussed in this article, where it is suggested that the support may alter the catalytic behavior through both electronic and dispersional effects.

TL;DR: In this article, a large fraction of the Pt becomes "inaccessible" to hydrogen chemisorption upon treatment in hydrogen at high temperature (> 500 °C) and the results agree with the assumption that the highly dispersed particles form an alloy with the Al from the support.

TL;DR: In this article, the authors investigated the effect of the number of hydroxyl groups present and the temperature of the catalyst on SO 2 adsorption on a γ-alumina (Al 2 O 3 ) catalyst.

TL;DR: In this paper, changes in dispersion of alumina supported Pt, Ir, and Rh catalysts due to thermal treatment (250-800 °C) in oxygen and hydrogen atmospheres were measured.

TL;DR: In this article, the molecular sieving effect among alkyl aromatics and aliphatics of varying length and degree of branching is described, and the new zeolite is characterized by a series of diagnostic catalytic reactions.

TL;DR: In this article, the structure of molybdenum and cobalt species present in CoMo γ-Al 2 O 3 (Co Mo atomic ratio, 0.64) catalyst systems was analyzed using laser Raman spectroscopy.

TL;DR: In this paper, the specific catalysts for the reaction of CH4 with H2O have been obtained and have been shown to vary markedly with catalyst preparation and to differ considerably from the specific activities of pure nickel, which has been explained by suggesting that the unreduced catalysts contain surface nickel aluminate phases which, on reduction, give monodispersed nickel atoms closely associated with alumina sites in addition to metallic crystallites arising from the reduction of nickel oxide.

TL;DR: In this paper, the effects of substitution of deuterium for hydrogen in ethylene and propylene with 14C-labeled epoxides have been studied over a silver catalyst.

TL;DR: In this paper, the authors show the importance of octahedral coordination and the degree of surface hydration with respect to surface oxygen basicity for the formation of surface bicarbonates.

TL;DR: In this paper, the authors show that at high pressures the reactivity decreases with an increased number of rings in the reactant, which may be related to the concentrations of surface anion vacancies and the nature of the adsorbed intermediates.

TL;DR: In this paper, the Strukturen der Mound Co-Spezies in CoMo/y-Al,O3-Katalysatorsystemen werden mit Hilfe der Laser- Raman-Spektroskopie untersucht.

TL;DR: In this paper, the hydrogenation of cyclohexene was studied in both gas and liquid phases on six different palladium catalysts supported on silica gel and alumina between 264 and 308 K at hydrogen pressures from 4 to 89 kPa, cycloxide partial pressure from 0.46 to 1.5 kPa and cycloxide molar concentration of 0.15 to 3.0 M.

TL;DR: In this paper, a study of the effects of various heat treatments on the state of dispersion of platinum in alumina-supported catalysts has shown that during heat treatments in hydrogen and air the hydrogen-chemisorption capacity (expressed as the H Pt ratio) of the catalysts decreases.

TL;DR: In this article, the adsorption of NO was studied in the temperature range 300-500 K by low-energy electron diffraction (LEED), photoemission, and Auger electron spectroscopy on a smooth Pt(100) crystal exhibiting a 1 × 1, 5 × 20, or √29 × √170 structure.

TL;DR: In this article, isomerization and hydrogenolysis reactions of neopentane and neohexane were studied in the presence of excess hydrogen at 455 to 625 K in a flow reactor over various Pt/silica and Pt/Y-zeolite catalysts having dPt in the range 1 to 20 nm.

TL;DR: In this article, the interaction of Mo(CO) 6 with γ-alumina has been studied in the temperature range of −17 to 1000 °C and it is likely that most of the dominant surface species formed during the decomposition of the complex have been identified.

TL;DR: In this paper, a wide-angle X-ray scattering and transmission electron microscopy was used to evaluate the effect of support on the electron donor-acceptor ratio at the surface Au site, and it was shown that increased electron density at the site increases electron back donation from metal to adsorbed NO, weakening the N-O bond and facilitating the formation of Nz over that of NHS.

TL;DR: In this paper, the formation and stability of isocyanate complexes in the NO + CO reaction on a platinum catalyst were investigated using infrared spectroscopy combined with mass spectrometry.

TL;DR: In this paper, a model was developed that expresses the adsorption rate (R a ) of saturated hydrocarbons in terms of competition for chemisorption on the same "potential sites" on metal surfaces.