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Showing papers in "Journal of Catalysis in 1979"


Journal ArticleDOI
TL;DR: In this article, the X-ray diffraction, optical, and XPS-Auger studies are presented that describe the formation, electronic structure, and surface composition of low pressure methanol synthesis catalysts.

539 citations


Journal ArticleDOI
TL;DR: In this article, four types of carbon were observed to form on an alumina-supported nickel methanation catalyst on exposure to carbon monoxide at 550 ± 50 K. In order of their reactivity toward hydrogen, the carbon species may be classified as: chemisorbed carbon atoms (α), bulk nickel carbide, amorphous carbon (β), and crystalline elemental carbon.

356 citations


Journal ArticleDOI
TL;DR: Titania-supported nickel catalysts exhibit unusual properties in CO-H2 reactions relative to conventional Ni catalysts as mentioned in this paper, indicating a unique metal-support interaction in the Ni TiO 2 system.

343 citations


Journal ArticleDOI
TL;DR: In this paper, the role of surface carbon in the Fischer-Tropsch synthesis was investigated and it was shown that CO dissociates in a fast step to give carbidic intermediates, from which both methane and higher hydrocarbons are produced.

334 citations


Journal ArticleDOI
TL;DR: In this paper, the main features of the catalytic conversion process are discussed and a mechanism is suggested for the formation of sorbed C3,C4 olefinic residues, and for initial carbon-carbon bond formation from methanol.

308 citations


Journal ArticleDOI
TL;DR: The infrared spectra of the H-ZSM-5 zeolite calcined at temperatures up to 1173 K, and the corresponding electron spin resonance and microcalorimetric data are discussed in this paper.

287 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that platinum catalyzes the reduction of TiO 2 to Ti 4 O 7 and deposits as thin pill-box structures on the surface of the Ti O 7.

284 citations


Journal ArticleDOI
TL;DR: In this article, the surface species formed by adsorption of atomic hydrogen on alumina has been characterized by a desorption peak at 480 °C in the temperature-programmed desorptions.

269 citations


Journal ArticleDOI
TL;DR: In this article, the structural and spectroscopic properties of VOPO 4 and (VO) 2 P 2 O 7, whose presence is necessary to obtain a substantial selectivity in the range P:V = 05:1 to 2:1, have been examined in connection with those of V 2 O 5, where the excited atoms which are located on each side of the coherent boundaries formed in steady state conditions, are assumed to influence strongly the activity and selectivity.

233 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of thermal aging on catalytic activity was studied under oxidizing (air), inert (N2), and reducing (H2) conditions, and the results showed that small amounts of Ce oxide (0.6-1.3 wt% Ce) enhance the oxidation of CO over fresh Pt and Pd catalysts.

226 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the adsorption of H2 and CO could be partially restored if the sample in the SMSI state were treated with H2O vapor at 525 K or O2 at 875 K, the latter treatment being more effective.

Journal ArticleDOI
TL;DR: An analysis of the kinetic data for the conversion of methanol to hydrocarbons and the composition of light olefinic products suggests that autocatalytic reactions are important steps in the conversion process as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, the complexity of the metastable Fe/FexC/C system is further exemplified in a series of spectra recorded at intermediate reaction times, demonstrating time dependency of carbide phases formed and dependence of the rate of carbides formation on average metal particle size.

Journal ArticleDOI
TL;DR: In this paper, the authors used transmission electron microscopy (TEM) to study the behavior of Pt oxide on γ -Al 2 O 3 during various heat treatments and found that the Pt oxide concentration in the dispersed phase increases proportionally with Pt loading until a saturation concentration of 2.2 μ mol Pt/m 2 (BET) is reached.

Journal ArticleDOI
TL;DR: In this article, the effect of pressure on methanol conversion to hydrocarbons over ZSM-5 class zeolites has been investigated and the relative rates of the dehydration and aromatization steps in the reaction sequence were investigated.

Journal ArticleDOI
TL;DR: In situ constant velocity Mossbauer data have been used to measure the rate of carbiding of 10 Fe SiO 2 and 10 Fe MgO during the Fischer-Tropsch synthesis reaction at 523 °K and 3.3 H 2 CO as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, the conversion of synthesis gas to aromatic hydrocarbons over a new class of catalysts comprising a CO reduction function combined with a ZSM-5 class zeolite is reported.

Journal ArticleDOI
TL;DR: The catalytic activity of MnO 2 prepared by different methods has been determined from the initial rate of decomposition of H 2 O 2 and the conversion of CO to CO 2.

Journal ArticleDOI
TL;DR: The results of the coisomerization of 1-butene-d 0 d 8 showed that the reaction involved primarily an intramolecular hydrogen transfer as mentioned in this paper, indicating that the active sites consist of both basic and acidic sites.

Journal ArticleDOI
TL;DR: The interaction of anatase and rutile samples with V2O5, and their products, have been studied by thermal analysis, by ir and ESR spectroscopy and by X-ray diffraction as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, the reaction of a feed of equal weights of n-hexane (NC6), 3-methylpentane (3MP), 2,3-dimethylbutane, benzene, and toluene at 427/sup 0/C, 200 psig, and a 3:1 hydrogen-hydrocarbon ratio was studied on Y zeolites, L zeolite, mordenites, ferrierite and a large number of ZSM series.

Journal ArticleDOI
TL;DR: In this paper, it was shown that two-dimensional rafts of rhodium atoms of varying size can be detected in the ultradispersed state of alumina, and that the smallest size of a raft is 1.5 nm, corresponding to each raft having an average of 8 Rh atoms.

Journal ArticleDOI
TL;DR: In this article, the formation of "bimetallic clusters" supports the Alloy explanation for the improved performance of this type of bimetallic reforming catalyst, and it is shown that in the presence of adsorbed oxygen the Pt-Re clusters are thermodynamically unstable but that under mild conditions the rate of segregation is slow.

Journal ArticleDOI
TL;DR: In this article, the synthesis of hydrocarbons from CO and H2 was studied on a silica-supported Ru catalyst, and the species present on the catalyst surface were characterized by infrared spectroscopy.

Journal ArticleDOI
TL;DR: In this article, the authors used transmission electron microscopy to characterize the dispersions of CuO, ZnO, and Cr/sub 2/O/sub 3/ in methanol synthesis catalysts.

Journal ArticleDOI
TL;DR: An X-ray photoemission spectroscopy study of a series of standard nickel compounds (Ni, NiO, Ni(OH)2, NiSiO3) and silica-supported nickel methanation catalysts has been conducted.

Journal ArticleDOI
TL;DR: In this paper, the X-ray photoelectron spectroscopy (XPS) line shapes showed that two phases may exist at the surface of the catalytic phase of the catalyst.

Journal ArticleDOI
TL;DR: In this article, the structure, sintering rates and chemical composition of 20 to 200-A-diameter Pt-O and Pd-O alloys were examined using scanning transmission electron microscopy and energy dispersive X-ray microanalysis.

Journal ArticleDOI
TL;DR: In this article, the authors used limiting, model cases to describe dissociative, dual-site adsorption and showed that the values obtained for ΔSa0 must conform to certain rules in order to have any physical meaning.

Journal ArticleDOI
TL;DR: In this paper, the interaction between the functional OH groups on the internal and external surface and hexene-1 or n-hexane was elucidated by means of the transmission technique at various temperatures.