The Influence of Catalyst Restructuring on the Selective Hydrogenation of Acetylene to Ethylene

Jin, Yaming; Datye, Abhaya K.; Rightor, E. G.; Gulotty, Robert; Waterman, Wendy; Smith, M. R.; Holbrook, Michael T.; Maj, J. J.; Blackson, John

doi:10.1006/jcat.2001.3347

Cited by 151 publications

(97 citation statements)

References 15 publications

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“…In general, this behavior is similar to what has being observed for real Pd-Ag catalysts [1,27], thus suggesting that the model Pd-Ag catalysts studied here mimic the properties of the real catalysts.…”

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confidence: 86%

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Acetylene and Ethylene Hydrogenation on Alumina Supported Pd-Ag Model Catalysts

2006

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Adsorption and co-adsorption of ethylene, acetylene and hydrogen on Pd-Ag particles, supported on thin alumina films, have been studied by temperature programmed desorption (TPD). The TPD results show that adding of Ag to Pd suppresses overall hydrogenat ion activity but increases selectivity towards ethylene, i.e. similar to that observed on real catalysts. The results are rationalized on the basis of a complex interplay between surface and subsurface hydrogen species available in the system, whereby the latter species are the most critical for total hydrogenation of acetylene to ethane.

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confidence: 86%

“…Commercially, it is preferred to reduce the acetylene content to less than 10 ppm, which needs ~ 99% acetylene conversion in the excess of ethylene [1]. For the selective removal of acetylene, Pd catalysts are commonly used in industry [2], which are well known for their superior hydrogenation abilities.…”

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confidence: 99%

Acetylene and Ethylene Hydrogenation on Alumina Supported Pd-Ag Model Catalysts

2006

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“…Active-site isolation increases Pd-Pd distances on the catalyst surface and may lead to only weakly π-bonded acetylene on top of an isolated Pd atom. Furthermore, the sequential hydrogenation of acetylene to ethylene via vinyl and vinylidene intermediates requires a de fore, a reduction of neighbouring palladium sites on the surface should yield preferred hydrogenation of acetylene to ethylene [2,[11][12][13][14][15][16][17].…”

Section: Experimental T Ure Fmmentioning

confidence: 99%

Palladium–gallium intermetallic compounds for the selective hydrogenation of acetylenePart II: Surface characterization and catalytic performance

Osswald

Kovnir

Armbrüster

et al. 2008

Journal of Catalysis

312

234

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The structurally well-defined intermetallic compounds PdGa and Pd 3 Ga 7 constitute suitable catalysts for the selective hydrogenation of acetylene. The surface properties of PdGa and Pd 3 Ga 7 were characterized by X-ray photoelectron spectroscopy, ion scattering spectroscopy and CO chemisorption. Catalytic activity, selectivity and long-term stability of PdGa and Pd 3 Ga 7 were investigated under different acetylene hydrogenation reaction conditions, in absence and in excess of ethylene, in temperature-programmed and isothermal long-term experiments. Chemical treatment with ammonia solution -performed to remove the gallium oxide layer introduced during the milling procedure from the surface of the intermetallic compounds -yielded a significant increase in activity. Compared to Pd/Al 2 O 3 and Pd 20 Ag 80 reference catalysts, PdGa and Pd 3 Ga 7 exhibited a similar activity per surface area, but higher selectivity and stability. The superior catalytic properties are attributed to the isolation of active Pd sites in the crystallographic structure of PdGa and Pd 3 Ga 7 according to the active-site isolation concept.

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“…Catalyst surfaces that expose only isolated activesites exhibit a reduced number of possible adsorption geometries. Acetylene molecules will preferably be weakly π-bonded and the amount of di-σ-bonded acetylene as well as adsorbed ethylene and ethylidyne species will be reduced [7][8][9][10][11][12][13][14][15][16], leading to a smaller amount of oligomerisation products. Therefore, restricting the size of the active sites in a palladium containing hydrogenation catalyst and thereby preventing the formation of ensembles of neighboring Pd atoms on the surface -so-called active-site isolation -may increase the catalyst selectivity and long-term stability in acetylene hydrogenation.…”

Section: Introductionmentioning

confidence: 99%

Palladium–gallium intermetallic compounds for the selective hydrogenation of acetylenePart I: Preparation and structural investigation under reaction conditions

Osswald

Giedigkeit

Jentoft

et al. 2008

Journal of Catalysis

284

221

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The intermetallic compounds PdGa and Pd 3 Ga 7 are introduced as selective catalysts for the hydrogenation of acetylene. Single phase PdGa and Pd 3 Ga 7 can readily be prepared by the appropriate thermal treatment of the stoichiometric mixtures of the corresponding elements. The initial low surface areas of the as-prepared materials can be increased by careful mechanical treatment without decomposition. Detailed investigations of PdGa and Pd 3 Ga 7 by DSC/TG, in situ powder X-ray diffraction and in situ X-ray absorption spectroscopy during thermal treatment under various inert or reactive gas atmospheres showed a high thermal stability. The long-range and short-range order in the crystal structures remained intact up to temperatures of about 600 K. Neither phase transitions nor decomposition were detectable. In addition to high thermal stability -preserving the active-site isolation under reaction conditions -no incorporation of hydrogen or carbon in the intermetallic compounds under reducing conditions was observed. Besides being interesting model systems, palladium gallium intermetallic compounds are promising candidates for the application as highly selective hydrogenation catalysts.

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The Influence of Catalyst Restructuring on the Selective Hydrogenation of Acetylene to Ethylene

Cited by 151 publications

References 15 publications

Acetylene and Ethylene Hydrogenation on Alumina Supported Pd-Ag Model Catalysts

Acetylene and Ethylene Hydrogenation on Alumina Supported Pd-Ag Model Catalysts

Palladium–gallium intermetallic compounds for the selective hydrogenation of acetylenePart II: Surface characterization and catalytic performance

Palladium–gallium intermetallic compounds for the selective hydrogenation of acetylenePart I: Preparation and structural investigation under reaction conditions

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