Influence of surface structures, subsurface carbon and hydrogen, and surface alloying on the activity and selectivity of acetylene hydrogenation on Pd surfaces: A density functional theory study

Yang, Bo; Burch, Robbie; Hardacre, Christopher; Headdock, Gareth; Hu, P.

doi:10.1016/j.jcat.2013.05.027

Cited by 223 publications

(190 citation statements)

References 85 publications

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“…Such metals offer high alkene selectivity but typically require activation/use at elevated temperatures which limit widespread industrial use [7][8][9][10][11][12][13][14]. Selectivity over Pd based catalysts is believed to involve control over hydride formation which results in the formation of reactive subsurface hydrogen which is prone to hydrogenate ethylene to ethane upon migration back to the surface [15][16][17][18][19][20]. Recent surface science-studies indicate that the incorporation of C atoms into Pd nanoparticles play a crucial role in controlling the formation/diffusion of sub-surface hydrogen [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

McCue

Anderson

2015

Front. Chem. Sci. Eng.

229

196

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Recent advances with Pd containing catalysts for the selective hydrogenation of acetylene are described. The overview classifies enhancement of catalytic properties for monometallic and bimetallic Pd catalysts. Activity/ selectivity of Pd catalysts can be modified by controlling particle shape/morphology or immobilisation on a support which interacts strongly with Pd particles. In both cases enhanced ethylene selectivity is generally associated with modifying ethylene adsorption strength and/or changes to hydride formation. Inorganic and organic selectivity modifiers (i.e., species adsorbed onto Pd particle surface) have also been shown to enhance ethylene selectivity. Inorganic modifiers such as TiO 2 change Pd ensemble size and modify ethylene adsorption strength whereas organic modifiers such as diphenylsulfide are thought to create a surface template effect which favours acetylene adsorption with respect to ethylene. A number of metals and synthetic approaches have been explored to prepare Pd bimetallic catalysts. Examples where enhanced selectivity is observed are generally associated with decreased Pd ensemble size and/or hindering of the ease with which an unselective hydride phase is formed for Pd. A final class of bimetallic catalysts are discussed where Pd is not thought to be the primary reaction site but merely acts as a site where hydrogen dissociation and spillover occurs onto a second metal (Cu or Au) where the reaction takes place more selectively.

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Section: Introductionmentioning

confidence: 99%

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

McCue

Anderson

2015

Front. Chem. Sci. Eng.

229

196

View full text Add to dashboard Cite

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“…[3] Previous studies have suggested that subsurface Hspecies in Pd cause over-hydrogenation. [3][4][5] This process can be suppressed by alloying Pd with other metals such as Ag, Cu, or Au. [6][7][8] Controlling the morphologies [5] and modifications with ligands [9][10][11] have also been used to enhance the performance of Pd-based catalysts.T his phenomenon is often explained in terms of reducing the adsorption energy of ethylene by electronic and/or geometric effects.…”

mentioning

confidence: 99%

“…[3][4][5] This process can be suppressed by alloying Pd with other metals such as Ag, Cu, or Au. [6][7][8] Controlling the morphologies [5] and modifications with ligands [9][10][11] have also been used to enhance the performance of Pd-based catalysts.T his phenomenon is often explained in terms of reducing the adsorption energy of ethylene by electronic and/or geometric effects. [12,13] In addition, carbon monoxide has been used as am odifier to compete with ethylene for adsorption sites, which can improve the ethylene selectivity of supported Pd catalysts.…”

mentioning

confidence: 99%

Activation and Spillover of Hydrogen on Sub‐1 nm Palladium Nanoclusters Confined within Sodalite Zeolite for the Semi‐Hydrogenation of Alkynes

et al. 2019

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The search for efficient nontoxic catalysts able to perform industrial hydrogenations is at opic of interest, with relevance to many catalytic processes.H erein, we describe am echanistic phenomenon for the activation and spillover of hydrogen for remarkable selectivity in the semi-hydrogenation of acetylene over sub-1 nm Pd nanoclusters confined within sodalite (SOD) zeolite (Pd@SOD). Specifically,h ydrogen is dissociated on the Pd nanoclusters to form hydrogen species (i.e., hydrogen atoms and hydroxyl groups) that spill over the SOD surfaces.T he design and utilization of the small-pore zeolite SOD (six-membered rings with 0.28 0.28 nm channels) is crucial as it only allows H 2 diffusion into the channels to reacht he encapsulated Pd nanoclusters and thus avoids over-hydrogenation to form ethane.P d@SOD exhibits an ethylene selectivity of over 94.5 %, while that of conventional Pd/SOD is approximately 21.5 %.

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“…Oligomerization of C 2 H 2 can be effectively inhibited by high H 2 /C 2 H 2 ratios and high temperatures,r educing the formation of "green oil", [4,15,33,34] so ah igh temperature of 425 Ku sed in experiments is considered. Contributions of zero-point vibrational energy (ZPE), thermale nergy,a nd entropy to the molar Gibbs free energy have been included.…”

Section: Methodsmentioning

confidence: 99%

“…The entropies of gaseous H 2 ,C 2 H 2 ,a nd C 2 H 4 species under standard conditions are taken from experimental databases, and are used for calculating the entropies at 425 K. The total pressure is set to 1.0 atm along with an H 2 /C 2 H 2 ratio of 10:1,leadingt op artial pressures of H 2 ,C 2 H 2 ,a nd C 2 H 4 of 0.1, 0.01, and 0.89 atm, respectively, similart oe xperimental conditions used for comparison. [33] Further,i ti sf ound that the Pd-basedc atalysts during the C 2 H 2 hydrogenation reaction can form Pd hydride and Pd carbide owing to the formation of subsurface species like Ca nd Hs pecies, which can affect the selectivity of C 2 H 2 hydrogenation. [33,[35][36][37] Hu et al have proved that the subsurface Ha toms on the Pd catalyst can improve the selectivity of ethylene more than the pure Pd catalysts.…”

Section: Methodsmentioning

confidence: 99%

Cost‐Effective Palladium‐Doped Cu Bimetallic Materials to Tune Selectivity and Activity by using Doped Atom Ensembles as Active Sites for Efficient Removal of Acetylene from Ethylene

et al. 2018

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The catalytic activity and selectivity of cost‐effective noble‐metal‐doped common metal materials strongly depend on the doped atom ensemble in specific arrangements to provide active sites. In this study, aiming at insight into the doped atom ensembles as active sites for tuning the selectivity and activity towards the target reaction, different doped noble metal Pd atom ensembles for cost‐effective Pd‐doped Cu catalysts act as active sites to investigate the activity and selectivity towards the efficient removal of acetylene from ethylene by using density functional theory calculations. The results show that an ensemble composed of one surface and its joint sublayer Pd atoms in the Cu catalyst as active sites enhance both the selectivity and activity of C2H4 formation caused by adjusting the catalyst surface electronic structure. Moreover, the surface d‐band center of the Pd‐doped Cu catalyst can act as an effective “descriptor” for the rapid screening of catalytic activity in the design of improved catalysts with the noble‐metal‐doped common metal. Further, the ensemble composed of one surface and its joint sublayer doped Pd atoms as active sites in the cost‐effective Pd‐doped Cu bimetallic catalysts is an efficient approach to finely tune the activity and selectivity towards the efficient removal of acetylene from ethylene.

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Influence of surface structures, subsurface carbon and hydrogen, and surface alloying on the activity and selectivity of acetylene hydrogenation on Pd surfaces: A density functional theory study

Cited by 223 publications

References 85 publications

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

Activation and Spillover of Hydrogen on Sub‐1 nm Palladium Nanoclusters Confined within Sodalite Zeolite for the Semi‐Hydrogenation of Alkynes

Cost‐Effective Palladium‐Doped Cu Bimetallic Materials to Tune Selectivity and Activity by using Doped Atom Ensembles as Active Sites for Efficient Removal of Acetylene from Ethylene

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