A near-edge X-ray absorption fine structure and photoelectron spectroscopic study of the structure of acetylene on Pd(111) at low temperature

Hoffmann, Helmuth; Zaera, Francisco; Ormerod, R. Mark; Lambert, Richard M.; Yao, Jiachi; Saldin, D. K.; Wang, L.P.; Bennett, Dennis W.; Tysoe, Wilfred T.

doi:10.1016/0039-6028(92)90945-3

Cited by 82 publications

(35 citation statements)

References 25 publications

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“…Adsorbed acetylene distorts on Pd(1 1 1) below 200 K so that the carbon atoms are sp 2 hybridized [67][68][69]. The structure of acetylene has been measured on Pd(1 1 1) by LEED and is shown in Fig.…”

Section: Acetylene Cyclotrimerizationmentioning

confidence: 99%

Hydrocarbon conversion on palladium catalysts

Stacchiola

Calaza

Zheng

et al. 2005

Journal of Molecular Catalysis A: Chemical

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Section: Acetylene Cyclotrimerizationmentioning

confidence: 99%

Hydrocarbon conversion on palladium catalysts

Stacchiola

Calaza

Zheng

et al. 2005

Journal of Molecular Catalysis A: Chemical

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“…[31] We, therefore, not only studied the styrene-oxidation reaction on atomically precise [Au 25 18 ] À (Au 25 -i) catalysts, but also made an effort to understand the electronic structure of the catalysts by using a combination of synchrotron radiation-based XAFS and UPS, an approach rarely used previously. [32][33][34] XAFS (including X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS)) is a powerful tool to explore the local atomic and electronic structure of different kinds of gold nanoclusters. [20,[35][36][37][38][39][40][41][42][43][44][45][46] The UPS is particularly sensitive in the surface region (ca.…”

Section: Introductionmentioning

confidence: 99%

Ligand‐Stabilized and Atomically Precise Gold Nanocluster Catalysis: A Case Study for Correlating Fundamental Electronic Properties with Catalysis

Liu

Krishna

Losovyj

et al. 2013

Chemistry A European J

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We present results from our investigations into correlating the styrene-oxidation catalysis of atomically precise mixed-ligand biicosahedral-structure [Au25(PPh3)10(SC12H25)5Cl2](2+) (Au25-bi) and thiol-stabilized icosahedral core-shell-structure [Au25(SCH2CH2Ph)18](-) (Au25-i) clusters with their electronic and atomic structure by using a combination of synchrotron radiation-based X-ray absorption fine-structure spectroscopy (XAFS) and ultraviolet photoemission spectroscopy (UPS). Compared to bulk Au, XAFS revealed low Au-Au coordination, Au-Au bond contraction and higher d-band vacancies in both the ligand-stabilized Au clusters. The ligands were found not only to act as colloidal stabilizers, but also as d-band electron acceptor for Au atoms. Au25-bi clusters have a higher first-shell Au coordination number than Au25-i, whereas Au25-bi and Au25-i clusters have the same number of Au atoms. The UPS revealed a trend of narrower d-band width, with apparent d-band spin-orbit splitting and higher binding energy of d-band center position for Au25-bi and Au25-i. We propose that the differences in their d-band unoccupied state population are likely to be responsible for differences in their catalytic activity and selectivity. The findings reported herein help to understand the catalysis of atomically precise ligand-stabilized metal clusters by correlating their atomic or electronic properties with catalytic activity.

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“…In this case, cyclo-trimerization seems to occur through the rapid formation of the C4H4 metallocyclic intermediate species (Ormerod et al, 1993a;Pacchioni and Lambert, 1994;Ramirez-Cuesta et al, 1995). This species can then react with another adsorbed C2H2 species to form C6H6 (Hoffmann et al, 1992;Janssens et al, 1998;Ormerod et al, 1991;Patterson and Lambert, 1988;Patterson et al, 1989) or 2 C4H4 molecules react together to form cyclo-octatetraene (C8H8) which then thermally decomposes to yield C6H6 and C2H2 (Pacchioni and Lambert, 1994;Ramirez-Cuesta et al, 1995). Interestingly, cyclo-trimerization of C2H2 does not occur on MgO (Abbet et al, 2001), which is a substrate perhaps more relevant to cosmic dust analogues.…”

Section: Titanmentioning

confidence: 99%

Uptake of acetylene on cosmic dust and production of benzene in Titan's atmosphere

Frankland

James

Carrillo‐Sánchez

et al. 2016

Icarus

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A low-temperature flow tube and ultra-high vacuum apparatus were used to explore the uptake and heterogeneous chemistry of acetylene (C2H2) on cosmic dust analogues over the temperature range encountered T below 600 km. The uptake coefficient, , was measured at 181 K to be (1.6 ± 0.4) × 10 -4 , (1.9 ± 0.4) × 10 -4 and (1.5 ± 0.4) × 10 -4 for the uptake of C2H2 on Mg2SiO4, MgFeSiO4 and Fe2SiO4, respectively, indicating that  is independent of Mg or Fe active sites. The uptake of C2H2 was also measured on SiO2 and SiC as analogues for meteoric smoke particles T but was found to be below the detection limit ( < 6 × 10 -8 and < 4 × 10 -7 , respectively). The rate of cyclo-trimerization of C2H2 to C6H6 was found to be 2.6 × 10 -5 exp(-741/T) s -1 , with an uncertainty ranging from ± 27 % at 115 K to ± 49 % at 181 K. A chemical ablation model was used to show that the bulk of cosmic dust particles (radius 0.02 -10  T mass loss through sputtering), thereby providing a significant surface for heterogeneous 2 chemistry. A 1D model of dust sedimentation shows that the production of C6H6 via uptake of C2H2 on cosmic dust, followed by cyclo-trimerization and desorption, is probably competitive with gas-phase production of C6H6 between 80 and 120 km.

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A near-edge X-ray absorption fine structure and photoelectron spectroscopic study of the structure of acetylene on Pd(111) at low temperature

Cited by 82 publications

References 25 publications

Hydrocarbon conversion on palladium catalysts

Hydrocarbon conversion on palladium catalysts

Ligand‐Stabilized and Atomically Precise Gold Nanocluster Catalysis: A Case Study for Correlating Fundamental Electronic Properties with Catalysis

Uptake of acetylene on cosmic dust and production of benzene in Titan's atmosphere

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