The polymerization of acetylene on supported metal clusters

Gilb, Stefan; Arenz, Matthias; Heiz, Ulrich

doi:10.1063/1.2389021

Cited by 9 publications

(6 citation statements)

References 30 publications

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“…4). Increasing the size of deposited clusters to Pd 4 has a significant influence in product distribution during the polymerization of acetylene as significant quantities of C 4 H 6 are detected at low temperature 87 . Such insights can only be obtained via synthesis methods that can precisely control particle size with atomic resolution.…”

Section: (Ref 92)mentioning

confidence: 99%

“…Carbon monoxide oxidation 86 is the model reaction most widely studied due to its simplicity and significance. Subsequently, more complex reactions have been investigated including acetylene cyclotrimerization 86,87 and hydrazine decomposition 88 . Such model studies are fruitful in elucidating the basic mechanism of a catalytic process and determining the influence of cluster size as well as support interactions leading to enhanced catalytic systems.…”

Section: Uhv Studies Of Supported Size-selected Clustersmentioning

confidence: 99%

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Catalysis by clusters with precise numbers of atoms

2015

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Clusters that contain only a small number of atoms can exhibit unique and often unexpected properties. The clusters are of particular interest in catalysis because they can act as individual active sites, and minor changes in size and composition--such as the addition or removal of a single atom--can have a substantial influence on the activity and selectivity of a reaction. Here, we review recent progress in the synthesis and characterization of well-defined subnanometre clusters, and the understanding and exploitation of their catalytic properties. We examine work on size-selected supported clusters in ultrahigh-vacuum environments and under realistic reaction conditions, and explore the use of computational methods to provide a mechanistic understanding of their catalytic properties. We also highlight the potential of size-selected clusters to provide insights into important catalytic processes and their use in the development of novel catalytic systems.

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Section: (Ref 92)mentioning

confidence: 99%

Section: Uhv Studies Of Supported Size-selected Clustersmentioning

confidence: 99%

Catalysis by clusters with precise numbers of atoms

2015

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“…To understand the mechanisms of the benzene formation from acetylene, single-crystal surfaces of various metals, bimetallic systems, and metal oxides under ultrahigh vacuum to atmospheric pressure conditions have been used as model catalysts; Pd(111), Cu(111), Pd/W(211), Sn/Pt(111), reduced TiO 2 (001), , and so forth were found to be catalytic. Supported Pd n clusters with n = 1−30 were also studied to selectively catalyze this reaction. ,, …”

Section: Introductionmentioning

confidence: 99%

Acetylene Cyclotrimerization Catalyzed by TiO₂ and VO₂ in the Gas Phase: A DFT Study

Wang

et al. 2008

J. Phys. Chem. A

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Density functional theory (DFT) calculations have been used to investigate acetylene cyclotrimerization catalyzed by titanium and vanadium dioxides. The calculated results illustrate that the overall process is highly favorable at room temperature from both thermodynamic and kinetic points of view. The mechanism of C2H2 cyclotrimerization over MO2 (M = Ti, V) can be understood as four steps: (1) a four-membered ring (-O-M-C=C-) formation that coordinates and activates the first C2H2 molecule; (2) the second C2H2 insertion into the M-C bond to form a six-membered ring (-O-M-C=C-C=C-); (3) the third C2H2 insertion into the M-C bond to form an eight-membered ring (-O-M-C=C-C=C-C=C-); and (4) contraction of the eight-membered ring and benzene formation and desorption. All of the reaction steps are overall barrierless with respect to the separated reactants (MO2C2xH2x + C2H2, x = 0, 1, 2). This theoretical study predicts that the M=O double bond in MO2 is very catalytic toward the C2H2 cyclotrimerization. The metal center in this study can be considered always in the same +4 oxidation state (Ti4+ and V4+). In contrast, two-electron cycling of the metal center is present in the documented mechanism for the C2H2 cyclotrimerization. The C2H2 cyclotrimerization over the Ti atom and TiO molecule is also studied, and the documented mechanism applies in this case. The new mechanism is suggested to apply to reactions using titanium and vanadium oxides as catalysts.

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“…Traditional thermal semi-hydrogenation (TSH) employs hydrogen (H 2 ) as the H source; therefore, the safety issue cannot be ignored as H 2 is explosive . In addition, the deactivation of the nanocatalysts, , oligomerization of alkenes, , and the easy over-hydrogenation to alkanes , in TSH are tough problems to be resolved. Surface and interfacial modification to poison highly active nanosize Pd catalysts is an effective strategy to improve the alkene selectivity in TSH but at the expense of decreasing the conversion rate of alkynes. ,− Reducing the particle size of the Pd catalyst from the nanoscale to atomically dispersed Pd sites is an efficient approach to improve alkyne conversion rate and alkene selectivity synchronously; however, the catalyst cost and safety issue are still serious concerns .…”

Section: Introductionmentioning

confidence: 99%

Effect of Crystal Planes of Pd and the Structure of Interfacial Water on the Electrocatalytic Hydrogenation of Alkynes to Alkenes

Kui

et al. 2023

ACS Appl. Nano Mater.

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Efficient electrochemical semi-hydrogenation (ECSH) of alkynes to alkenes is a promising alternative to traditional thermal semihydrogenation. Mechanistic understanding of crystal plane-dependent ECSH performance is extremely important for the subsequent catalyst design. Here, we investigate the role of low-index Pd(hkl) surfaces, including Pd ( 100), ( 111), and (110) planes, in ECSH of alkynes. As a result, alkyne conversion rate and alkene selectivity of Pd(hkl) surfaces follow the order of Pd (100) > Pd (111) > Pd (110). In situ Raman spectroscopic evidence indicates that the Pd (100) plane effectively enhances the formation of K + ion hydrated water and two-coordinated hydrogen-bonded water to accelerate semi-hydrogenation rate and improve alkene selectivity, respectively. The order of the ability to regulate the interfacial water structure is ideally consistent with that of ECSH performance on Pd(hkl) surfaces. Pd nanocubes enclosed by the (100) surface exhibit excellent ECSH activity, alkene selectivity, and cycling stability. These findings demonstrate that the interfacial water structure is crystal plane-dependent, which is the determining factor for ECSH.

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The polymerization of acetylene on supported metal clusters

Cited by 9 publications

References 30 publications

Catalysis by clusters with precise numbers of atoms

Catalysis by clusters with precise numbers of atoms

Acetylene Cyclotrimerization Catalyzed by TiO₂ and VO₂ in the Gas Phase: A DFT Study

Effect of Crystal Planes of Pd and the Structure of Interfacial Water on the Electrocatalytic Hydrogenation of Alkynes to Alkenes

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The polymerization of acetylene on supported metal clusters

Cited by 9 publications

References 30 publications

Catalysis by clusters with precise numbers of atoms

Catalysis by clusters with precise numbers of atoms

Acetylene Cyclotrimerization Catalyzed by TiO2 and VO2 in the Gas Phase: A DFT Study

Effect of Crystal Planes of Pd and the Structure of Interfacial Water on the Electrocatalytic Hydrogenation of Alkynes to Alkenes

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Product

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Acetylene Cyclotrimerization Catalyzed by TiO₂ and VO₂ in the Gas Phase: A DFT Study