Atomic and molecular adsorption on Pt(111)

Ford, Denise C.; Xu, Ye; Mavrikakis, Manos

doi:10.1016/j.susc.2005.04.028

Cited by 259 publications

(272 citation statements)

References 94 publications

(155 reference statements)

Supporting

Mentioning

217

Contrasting

Order By: Relevance

“…On the other hand, the frequency of the Pt-H stretching mode is not affected: The trajectory of the adsorbate in the interval 5.5 -5.9 ps, during which it stays at an atop site, yields 2286 cm À1 for the Pt-H stretching mode; the deuteron to proton isotope factor, 1.41, was taken into account to obtain the frequency. The frequency is almost the same as that for Pt (111) lation 27) and is comparable with the experimentally measured frequency. 28) The Pt-H vibration and the potential surface for H-diffusion are thus affected differently by the water.…”

Section: Electron Transfer and Surface Diffusionsupporting

confidence: 86%

Electrode Dynamics from First Principles

et al. 2008

View full text Add to dashboard Cite

The investigation of electrode dynamics has been a major topic in the field of electrochemistry for a century. Electrode dynamics consist of electron transfer reactions that give rise to, or are caused by, a bias voltage, and are influenced by surface catalysis, electrolyte solution, transport of electrons and ions. The first-principles molecular dynamics simulation of the electrochemical system has been hampered by the difficulty to describe the bias voltage and the complex solution-electrode interface structure. Here we utilize a new algorithm called the effective screening medium to characterize the biased interface between platinum and liquid water, revealing the microscopic details of the first, Volmer, step of the platinum-catalyzed hydrogen evolution reaction. By clarifying the important roles played by both the water and the bias, we show why this reaction occurs so efficiently at the interface. Our simulations make a significant step towards a deeper understanding of electrochemical reactions.

show abstract

Section: Electron Transfer and Surface Diffusionsupporting

confidence: 86%

Electrode Dynamics from First Principles

et al. 2008

View full text Add to dashboard Cite

show abstract

“…We have previously shown that at these conditions methionine decomposes to SCH 3 moieties that bind to the Pd catalyst, but that it does not decompose completely to yield atomic sulfur [19]. In contrast, the fractional uptake observed on Pt and Ni is consistent with the saturation coverage by atomic sulfur on the close-packed facets of each metal [35,36]. These results, then, are suggestive of the decomposition of methionine to form atomic sulfur on Pt and Ni.…”

Section: Discussionmentioning

confidence: 76%

Inhibition of Metal Hydrogenation Catalysts by Biogenic Impurities

2014

View full text Add to dashboard Cite

We show that supported Ni, Pt, and Pd catalysts used for liquid phase hydrogenation are inhibited by the biogenic impurities present in biologically-derived feedstocks used to produce high-value chemicals. The effects of thiamine HCl, cysteine, methionine, biotin, tryptophan, niacin, threonine, and p-aminobenzoic acid were elucidated by collecting adsorption isotherms of these species and by quantifying their influence on the rate of cyclohexene hydrogenation at 323 K. Inhibition increases in the order of Pd \ Pt \ Ni and generally correlates with the binding energies of sulfur and nitrogen. The equilibrium constants reported here for adsorption of these species on Ni, Pt, and Pd can facilitate the design of separation systems and new catalysts used for upgrading biologically-produced platform molecules.

show abstract

“…The next step is to estimate values of binding energies for adsorption of all species on the surface, for example using experimental results from the literature, results from DFT calculations, or scaling relations (20)(21)(22)(23)(24). In addition, it is necessary to estimate values for the entropies of the adsorbed species, for example using results from experimental studies (25), correlations in the literature (26), results from DFT calculations of vibrational frequencies (27)(28)(29)(30)(31)(32)(33)(34), combined with hindered translator and hindered rotor models for the three modes associated with motion parallel to the surface (35,36), or by assuming models for the extent of mobility on the surface. It is now possible to estimate values for lumped equilibrium constants, K ads,i , to form the adsorbed species from the reactants and/or products, followed by calculation of θ p .…”

Section: Analytical Strategy For Analysis Of Reaction Schemesmentioning

confidence: 99%

Analysis of reaction schemes using maximum rates of constituent steps

Motagamwala

Dumesic

2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, r max,i , assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of r max,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of r max,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps.chemical kinetics | catalysis | microkinetics C hemical reactions take place through sequences of elementary steps, and the dynamics of the overall stoichiometric reaction are typically controlled by key steps in this sequence of steps. For example, in the case of a catalytic reaction, the reaction kinetics are controlled by the energetics of the transition states for the rate-controlling steps and by the energetics of species that are abundant on the active sites (i.e., the Gibbs free energies of these transition states and adsorbed species relative to the reactants and products of the overall stoichiometric reaction). However, whereas the observed reaction kinetics are controlled by a limited number of transition states and adsorbed species, it is typically required to carry out detailed microkinetic analyses to identify the nature of these key transition states and adsorbed species. Thus, a general strategy to elucidate how the reaction kinetics are controlled by a proposed reaction mechanism is first to carry out density functional theory (DFT) calculations to determine the thermodynamic properties of all adsorbed species and transition states, and then to build a microkinetic model to determine the surface coverages by all adsorbed species and the forward and reverse rates of all elementary steps for a range of reaction conditions (1-5). Sensitivity analyses are then carried out using this microkineti...

show abstract

Atomic and molecular adsorption on Pt(111)

Cited by 259 publications

References 94 publications

Electrode Dynamics from First Principles

Electrode Dynamics from First Principles

Inhibition of Metal Hydrogenation Catalysts by Biogenic Impurities

Analysis of reaction schemes using maximum rates of constituent steps

Contact Info

Product

Resources

About