Planar Models for Alumina-Based Catalysts

Cocke, David L.; Johnson, E.; Merrill, Robert P.

doi:10.1080/01614948408078064

Cited by 161 publications

(108 citation statements)

References 280 publications

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“…These voltages correspond to alumina and titania thicknesses of about 14.0 nm [56] and 30.0 nm [55]. The formed alumina layers are described as amorphous or γ-and γ ′ -Al 2 O 3 [57,58]. In the case of TiO 2 , the stoichiometric modifications anatase, rutile and brookite, as well as non-stoichiometric phases were observed [55,59].…”

Section: Sample Preparationmentioning

confidence: 99%

Strong metal–support interactions on rhodium model catalysts

Linsmeier

Taglauer

2011

Applied Catalysis A: General

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Reactive processes on catalyst surfaces are studied in this work for Rh/metal oxide model systems by means of surface science techniques. Published results in the literature deal with titania, alumina, and silica as support materials and are briefly reviewed. For the present studies Rh/Al 2 O 3 and Rh/TiO 2 model catalysts with about one monolayer Rh coverage are specially prepared and analyzed by ion scattering spectroscopy, X-ray photoelectron spectroscopy, and thermal desorption measurements as main techniques. In part these measurements are supported by a variety of other analytical and imaging techniques. For thermal treatment in hydrogen atmosphere at low and elevated pressures a complete Rh encapsulation by titania is observed for temperatures above 773 K. The results from ion bombardment depth profiling are corroborated by the concomitant drastic reduction of the CO adsorption capacity of these samples. The model catalysts thus exhibit the typical features of 'strong metal-support interaction'. The effect was not found for alumina supports, for which thermal treatments mainly resulted in gradual interdiffusion of the various surface species. These results also demonstrate that characteristic catalyst behavior can be successfully studied by applying surface science methods to model catalysts.

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Section: Sample Preparationmentioning

confidence: 99%

Strong metal–support interactions on rhodium model catalysts

Linsmeier

Taglauer

2011

Applied Catalysis A: General

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“…Maghemite may also form by the thermal decomposition of Akaganeite, which contains no Fe~ (Gonzales-Calbet and Alario Franco, 1982). Similarly, each time chemists heat boehmite to get spinel-type aluminas (3"-, ~-, 0-, n-A12Oa), they do not question the absence of AI~ in boehmite (see, e.g., Coke et aL, 1984;L6onard et al, 1967). Finally ferrihydrite aged at moderate temperature (92"C) directly transforms to hematite instead ofmaghemite (Johnson and Lewis, 1983).…”

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New Data and a Revised Structural Model for Ferrihydrite: Comment

Manceau

1990

Clays and clay miner.

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“…The entire observed peaks can easily attributed to Al 3+ linked to oxygen. 53,54 Those at 73.6 and 73.5 eV can be assigned to the bonds Al-O in oxides spinel, 55 the others, Table 2. The results of the BET measurements: the surface area (SBET), the pore volume (Vp) and the pore size (dBET) (x = 0-1.0) …”

Section: (2)mentioning

confidence: 99%

Synthesis and Characterization of Zn_(1-x)Ni_xAl₂O₄Spinels as a New Heterogeneous Catalyst of Biginelli's Reaction

Akika¹,

Kihal²,

Habila³

et al. 2013

Bulletin of the Korean Chemical Society

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Zn (1-x) Ni x Al 2 O 4 (x = 0.0-1.0) spinels were prepared at 800 °C by co-precipitation method and characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The specific surface area was determined by BET. SEM image showed nano sized spherical particles. XPS confirmed the valence states of the metals, showing moderate Lewis character for the surface of materials. The powders were successfully used as new heterogeneous catalysts of Biginelli's reaction, a one-pot threecomponent reaction, leading to some dihydropyrimidinones (DHPMs). These new catalysts that produced good yields of DHPMs, were easily recovered by simple filtration and subsequently reused with persistent activity, and they are non-toxic and environmentally friendly. The optimum amount of catalyst is 20% by weight of benzaldehyde derivatives, while the doping amount has been found optimal for x = 0.1.

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Planar Models for Alumina-Based Catalysts

Cited by 161 publications

References 280 publications

Strong metal–support interactions on rhodium model catalysts

Strong metal–support interactions on rhodium model catalysts

New Data and a Revised Structural Model for Ferrihydrite: Comment

Synthesis and Characterization of Zn_(1-x)Ni_xAl₂O₄Spinels as a New Heterogeneous Catalyst of Biginelli's Reaction

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Planar Models for Alumina-Based Catalysts

Cited by 161 publications

References 280 publications

Strong metal–support interactions on rhodium model catalysts

Strong metal–support interactions on rhodium model catalysts

New Data and a Revised Structural Model for Ferrihydrite: Comment

Synthesis and Characterization of Zn(1-x)NixAl2O4Spinels as a New Heterogeneous Catalyst of Biginelli's Reaction

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Product

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Synthesis and Characterization of Zn_(1-x)Ni_xAl₂O₄Spinels as a New Heterogeneous Catalyst of Biginelli's Reaction