Electrochemical studies of irreversibly adsorbed ethyl pyruvate on Pt{hkl} and epitaxial Pd/Pt{hkl} adlayers

Hazzazi, Omar A.; Huxter, Sharon Elizabeth; Taylor, R B; Palmer, Benjamin A.; Gilbert, Lee Alexander; Attard, Gary Anthony

doi:10.1016/j.jelechem.2009.12.026

Cited by 13 publications

(27 citation statements)

References 102 publications

(131 reference statements)

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“…Decarbonylation takes place only at the Pt(100) electrode, which we derive from both the stripping behavior of the formed adsorbate and surface-enhanced raman spectroscopy (SERS) as well as Fourier transform infrared (FTIR) spectroscopy measurements. In accordance with Hazzazi et al, we conclude that dissociative acetone adsorption requires a (100) geometry featuring more than two neighboring platinum atoms.…”

Section: Introductionsupporting

confidence: 92%

“…This is in line with the results presented by Hazzazi et al, who arrived at a similar conclusion for ethyl pyruvate. 6 We suggest that cleavage of the C–C bond requires adsorption of the C=C bond of the enol tautomer in a geometry in which each of the C atoms binds to opposing bridge sites. Such a geometry only exists at Pt(100) terraces and comprises 4 surface atoms.…”

Section: Discussionmentioning

confidence: 88%

“…Previous experiments have revealed that ethyl pyruvate—another carbonyl compound—adsorbs under decarbonylation (that is, CO formation) at all platinum surfaces, 15 whereas stripping experiments suggest that decarbonylation occurs mainly on Pt(100) electrodes. 6 In the present work, acetone is adsorbed to a variety of platinum single-crystal electrodes. After electrolyte exchange under potential control, stripping experiments under both reductive and oxidative conditions are conducted.…”

Section: Introductionmentioning

confidence: 99%

“…Biomass could become a crucial feedstock for fuels and chemicals in the future . For that reason, the electrochemical hydrogenation of carbonyl compounds, as a means for the upgrading of pyrolysis oil − or the conversion of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran or 2,5-dimethylfuran, , has attracted much attention. Because of the increasing interest in the electrochemical conversion of carbonyl compounds, we recently investigated the electrochemical hydrogenation of acetone as a model compound for more complex carbonyl compounds. − In these studies, we found that the nature of the reaction undergone by acetone depends significantly on the crystallographic orientation of the platinum single-crystal electrode. , Specifically, no reaction occurs at the Pt(111) electrode because acetone does not bind to surfaces featuring high coordination numbers. , The hydrogenation of acetone occurs only at step sites, whereas the step geometry determines whether the reaction yields 2-propanol or propane. ,, Finally, a reaction occurs at Pt(100) terraces that leads to poisoning .…”

Section: Introductionmentioning

confidence: 99%

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Dissociative Adsorption of Acetone on Platinum Single-Crystal Electrodes

2021

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In this article, we investigate the poisoning reaction that occurs at platinum electrodes during the electrocatalytic hydrogenation of acetone. A better understanding of this poisoning reaction is important to develop electrocatalysts that are both active for the hydrogenation of carbonyl compounds and resilient against poisoning side reactions. We adsorb acetone to Pt(331), Pt(911), Pt(510), and Pt(533) (i.e., Pt[2(111) × (110)], Pt[5(100) × (111)], [5(100) × (110)], and Pt[4(111) × (100), respectively])) as well as Pt(100) single-crystal electrodes and perform reductive and oxidative stripping experiments after electrolyte exchange. We found that acetone adsorbs molecularly intact on all sites apart from Pt(100) terrace sites and can be stripped reductively from the electrode surface at a potential positive of hydrogen evolution. However, at Pt(100) terraces, acetone adsorbs dissociatively as carbon monoxide, which remains attached to the electrode surface and leads to its poisoning. Strikingly, dissociative adsorption does not occur on step sites with (100) geometry, which suggests that the dissociative adsorption of acetone is limited to Pt(100) terraces featuring a certain minimum “ensemble” number of freely available Pt atoms.

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Section: Introductionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dissociative Adsorption of Acetone on Platinum Single-Crystal Electrodes

2021

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“…The study of single crystals can directly access this, although great care must be taken, given the intrinsically low surface area of the system. Although obtaining single crystal samples can be costly, for some systems epitaxial films can be prepared atop an oriented substrate ( Hazzazi et al., 2010 ) to reduce cost and increase throughput. The results obtained from such studies can provide important information in designing high-surface-area systems, discussed in more detail later, and offer an experimental analog to typically modeled systems using, e.g., density functional theory (DFT).…”

Section: Introductionmentioning

confidence: 99%

Understanding the Role of Surface Heterogeneities in Electrosynthesis Reactions

et al. 2020

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Summary In this perspective, we highlight the role of surface heterogeneity in electrosynthesis reactions. Heterogeneities may come in the form of distinct crystallographic facets, boundaries between facets or grains, or point defects. We approach this topic from a foundation of surface science, where signatures from model systems provide understanding of observations on more complex and higher-surface-area materials. In parallel, probe-based techniques can inform directly on spatial variation across electrode surfaces. We call attention to the role spectroscopy can play in understanding the impact of these heterogeneities in electrocatalyst activity and selectivity, particularly where these surface features have effects extending into the electrolyte double layer.

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Spontaneous Transmission of Chirality through Multiple Length Scales

Iski

Tierney

Jewell

et al. 2011

Chemistry A European J

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The hierarchical transfer of chirality in nature, from the nano-, to meso-, to macroscopic length scales, is very complex, and as of yet, not well understood. The advent of scanning probes has allowed chirality to be monitored at the single molecule or monolayer level and has opened up the possibility to track enantiospecific interactions and chiral self-assembly with molecular-scale detail. This paper describes the self-assembly of a simple, model molecule (naphtho[2,3-a]pyrene) that is achiral in the gas phase, but becomes chiral when adsorbed on a surface. This polyaromatic hydrocarbon forms a stable and reversibly ordered system on Cu(111) in which the transmission of chirality from single surface-bound molecules to complex 2D chiral architectures can be monitored as a function of molecular packing density and surface temperature. In addition to the point chirality of the surface-bound molecule, the unit cell of the molecular domains was also found to be chiral due to the incommensurate alignment of the molecular rows with respect to the underlying metal lattice. These molecular domains always aggregated in groups of three, all of the same chirality, but with different rotational orientations, forming homochiral "tri-lobe" ensembles. At a larger length scale, these tri-lobe ensembles associated with nearest-neighbor tri-lobe units of opposite chirality at lower packing densities before forming an extended array of homochiral tri-lobe ensembles at higher converges. This system displayed chirality at a variety of size scales from the molecular (≈1 nm) and domain (≈5 nm) to the tri-lobe ensemble (≈10 nm) and extended array (>25 nm) levels. The chirality of the tri-lobe ensembles dictated how the overall surface packing occurred and both homo- and heterochiral arrays could be reproducibly and reversibly formed and interchanged as a function of surface coverage. Finally, these chirally templated surfaces displayed remarkable enantiospecificity for naphtho[2,3-a]pyrene molecules adsorbed in the second layer. Given its simplicity, reversibility, and rich degree of order, this system represents an ideal test bed for the investigation of symmetry breaking and the hierarchical transmission of chirality through multiple length scales.

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Electrochemical studies of irreversibly adsorbed ethyl pyruvate on Pt{hkl} and epitaxial Pd/Pt{hkl} adlayers

Cited by 13 publications

References 102 publications

Dissociative Adsorption of Acetone on Platinum Single-Crystal Electrodes

Dissociative Adsorption of Acetone on Platinum Single-Crystal Electrodes

Understanding the Role of Surface Heterogeneities in Electrosynthesis Reactions

Spontaneous Transmission of Chirality through Multiple Length Scales

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