Decomposition of 1,1-Dichloroethene on Pd(111)

Hunka, Deborah E.; Herman, Daniel C.; Lormand, Kara D.; Jaramillo, Donna M.; Land, Donald P.

doi:10.1021/la050645i

Cited by 6 publications

(4 citation statements)

References 34 publications

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“…Among the studied model systems the edge of the Pd 7 /Au adsorbs DCE best, while adsorption on Pd layer /Au and Pd(111) surfaces is 0.3 eV and 0.4 eV weaker. TPD data obtained from the experiments on cis-and gem-DCE over the Pd(111) shows the cis-DCE desorption around 210 K. 64,65 A simple redhead analysis 66 translates this into adsorption energy of around À0.54 eV, (assuming a prefactor for desorption of 10 13 s À1 which differs B0.15 eV from our zeropoint energy corrected value. For 1,1-DCE, experiments indicate that molecules interacting directly with the palladium surface decompose rather than desorb from the surface.…”

Section: Adsorption On Pd(111) and Pd Islands The Comparison Of The T...mentioning

confidence: 88%

First principles investigations of Pd-on-Au nanostructures for trichloroethene catalytic removal from groundwater

Andersin

Honkala

2011

Phys. Chem. Chem. Phys.

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Catalytic groundwater remediation from chlorinated organic solvents like trichloroethene (TCE) has been found to be more effective and sustainable than traditional non-destructive methods. Among the experimentally studied catalyst materials, Pd-decorated Au nanoparticles show the highest activity and selectivity combined with the best resistance towards poisoning by chemicals present in groundwater. In this study the thermochemistry and adsorption geometries of TCE and its hydrodechlorination products are investigated via density functional theory calculations. Various model systems for Pd-supported Au nanoparticles are addressed. The adsorption of TCE is endothermic on bare Au(111), almost thermoneutral or slightly exothermic on Pd-Au surface alloys and clearly exothermic on Pd overlayer structures on Au(111). The strongest chemisorption is on the di-σ configuration between Pd atoms over the smallest 2D Pd clusters containing only a few Pd atoms. These are not, however, the best catalysts as they are too small to co-adsorb hydrogen needed for hydrodechlorination reaction. We demonstrate good correlation between adsorption energies and the d-band center of the system. The variation of adsorption energy from the one Pd-Au composition to the other can be tentatively assigned to be due to the ligand and coordination effects. Also, the ensemble effects are important; without the right ensemble the adsorption is weak or endothermic.

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Section: Adsorption On Pd(111) and Pd Islands The Comparison Of The T...mentioning

confidence: 88%

First principles investigations of Pd-on-Au nanostructures for trichloroethene catalytic removal from groundwater

Andersin

Honkala

2011

Phys. Chem. Chem. Phys.

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“…145 The kinetics of alkylidyne formation has been followed by RAIRS too. 146,147 RAIRS has also helped to identify the formation of ethylidyne and other alkylidynes during the surface activation of closely related reactants such as alkynes, 133,148,149 alkyls, 150,151 alkylidenes, 130,152 allyls, 153,154 vinyls, 149,155,156 and metallacyclic 157 surface species (sometimes via the intermediate formation of adsorbed olefins), via the decomposition of other molecules such as larger alkynes (propylidyne from either 2-hexene 158 or 3-hexyne [159][160][161] on Ru(0001), for instance) or unsaturated aldehydes, 162 by coupling of C 1 intermediates, 163,164 and even by hydrogenation of surface carbon atoms. 148 On the other hand, there are also cases where other surface intermediates are produced instead.…”

Section: Surface-science Experiments Using Model Catalysts: Uhvmentioning

confidence: 99%

New advances in the use of infrared absorption spectroscopy for the characterization of heterogeneous catalytic reactions

2014

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Infrared absorption spectroscopy has proven to be one of the most powerful spectroscopic techniques available for the characterization of catalytic systems. Although the history of IR absorption spectroscopy in catalysis is long, the technique continues to provide key fundamental information about a variety of catalysts and catalytic reactions, and to also offer novel options for the acquisition of new information on both reaction mechanisms and the nature of the solids used as catalysts. In this review, an overview is provided of the main contributions that have been derived from IR absorption spectroscopy studies of catalytic systems, and a discussion is included on new trends and new potential directions of research involving IR in catalysis. We start by briefly describing the power of Fourier-transform IR (FTIR) instruments and the main experimental IR setups available, namely, transmission (TIR), diffuse reflectance (DRIFTS), attenuated total reflection (ATR-IR), and reflection-absorption (RAIRS), for advancing research in catalysis. We then discuss the different environments under which IR characterization of catalysts is carried out, including in situ and operando studies of typical catalytic processes in gas-phase, research with model catalysts in ultrahigh vacuum (UHV) and so-called high-pressure cell instruments, and work involving liquid/solid interfaces. A presentation of the type of information extracted from IR data follows in terms of the identification of adsorbed intermediates, the characterization of the surfaces of the catalysts themselves, the quantitation of IR intensities to extract surface coverages, and the use of probe molecules to identify and titrate specific catalytic sites. Finally, the different options for carrying out kinetic studies with temporal resolution such as rapid-scan FTIR, step-scan FTIR, and the use of tunable lasers or synchrotron sources, and to obtain spatially resolved spectra, by sample rastering or by 2D imaging, are introduced.

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“…Furthermore, the electrochemical response and resulting nanocube deposits provide insights into the differences in electrochemistry between metallic and semiconducting SWCNTs. Obtaining shape-selective Pd deposits on SWCNTs provides a structure that can be tuned for specific applications in electronic, magnetic, or optical devices and enables further research into highly functionalized catalysts and face-selective reactions. , Because the nanoparticle shape dictates the arrangement of surface atoms, the ability to form specific shapes, such as cubes, creates the possibility of enhancing the sensing ability and catalytic properties of Pd. In contrast, nanoparticles of less-controlled or uncontrolled shapes, such as rough spheres, have unpredictable arrangements of surface atoms.…”

Section: Introductionmentioning

confidence: 99%

“…Metal nanoparticles have useful characteristics for applications in hydrogen detection and storage, chemical sensing, biological sensing, catalysis, and electronics . As with most nanostructures, the properties of nanoparticles are tuned by their size, shape, and crystal structure. , Additionally, many applications of nanoparticles require them to be electrically addresseda task not easily achieved with nanoparticles that are randomly dispersed during synthesis.…”

Section: Introductionmentioning

confidence: 99%

Controlled Decoration of Single-Walled Carbon Nanotubes with Pd Nanocubes

et al. 2007

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Although there have been many reports of nanoparticle-decorated single-walled carbon nanotubes (SWCNTs), the morphology of the resulting nanoparticles has lacked consistency and control. The present work demonstrates a process for decorating SWCNTs with Pd nanoparticles that have a tendency toward a selective and distinct cubic shape. SWCNTs were synthesized from an embedded catalyst in a porous anodic alumina (PAA) template. A single galvanostatic electrodeposition created Pd nanowires that contacted the SWCNTs within the pores and Pd nanoparticles that decorated the SWCNTs above the surface of the PAA. A distinct change in potential was observed as nanoparticles nucleated on the SWCNTs. The effects of current density and deposition time on the morphology of the nanoparticles were studied. Optimal deposition parameters yielded Pd nanocubes with smooth and flat facets. The electrochemical response and resulting nanocubic deposits provide insights into the difference in electrochemistry between metallic and semiconducting SWCNTs that are consistent with a disparity in the electron-transfer kinetics. Obtaining Pd nanoparticles of consistent shape that are electrically addressed by SWCNTs provides an improved structure for a variety of nanoparticle applications.

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Decomposition of 1,1-Dichloroethene on Pd(111)

Cited by 6 publications

References 34 publications

First principles investigations of Pd-on-Au nanostructures for trichloroethene catalytic removal from groundwater

First principles investigations of Pd-on-Au nanostructures for trichloroethene catalytic removal from groundwater

New advances in the use of infrared absorption spectroscopy for the characterization of heterogeneous catalytic reactions

Controlled Decoration of Single-Walled Carbon Nanotubes with Pd Nanocubes

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