The infrared spectrum of adsorbed carbon monoxide on a platinum surface in the presence of high pressure gas-phase carbon monoxide

Golden, William G.; Dunn, Douglas S.; Overend, John

doi:10.1021/j100496a017

Cited by 49 publications

(12 citation statements)

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“…There are subtle shifts in peak position, from 2077 cm -1 under vacuum to 2083 and 2062 cm -1 for the gas and liquid systems, respectively, but those can be explained by slight changes in surface coverages and surroundings. The frequencies observed in our experiments are indeed consistent with those previously reported under ultrahigh vacuum, − gas, , and liquid , environments. In addition, the IR peak intensities are comparable in all three cases, suggesting similar saturation coverages.…”

Section: Resultssupporting

confidence: 92%

In Situ Characterization of Adsorbates in Solid−Liquid Interfaces by Reflection−Absorption Infrared Spectroscopy

Kubota

Zaera

2003

Langmuir

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A cell has been designed for the in situ characterization of catalytic intermediates adsorbed at liquid−solid interfaces by single-reflection infrared spectroscopy. The design of our cell is based on previous setups used for the study of electrochemical systems, and consists of a cylindrical Teflon body terminated by a calcium fluoride prism cut in a trapezoidal shape with two faces beveled to 60° to let the infrared beam in and out of the cell on one end and by a polished platinum disk (the solid sample) mounted on a retractable rod on the other. The solid sample is cleaned by repeated electrochemical oxidation−reduction cycles using KClO4, HClO4, or H2SO4 electrolytes, and a thin liquid film is then trapped between the two surfaces for the liquid−solid adsorption studies. The performance of this cell was first tested by studies on the adsorption of carbon monoxide from 1.0 M H2SO4 solutions. Significant signals were detected for the adsorbed CO, comparable to those seen under vacuum or under high pressures of CO gas, and also to data reported previously. A more detailed characterization of our experimental setup was carried out with cinchona alkaloids. Discrimination between adsorbed and dissolved species was accomplished by dividing spectra obtained with p- and s-polarized light, and was corroborated by a number of tests, including a variation in the liquid film thickness and the nature of the adsorbing surface. The importance of the in situ characterization was assessed by comparing spectra for quinoline deposited under vacuum versus adsorbed from a carbon tetrachloride solution.

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Section: Resultssupporting

confidence: 92%

In Situ Characterization of Adsorbates in Solid−Liquid Interfaces by Reflection−Absorption Infrared Spectroscopy

Kubota

Zaera

2003

Langmuir

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“…It has been shown that RAIRS can be used to study CO adsorption at relatively high pressures (≤10 mbar) by normalizing the desired spectrum against a spectrum taken at the same pressure at high temperatures (1000 K), where hardly any CO is adsorbed at the surface. , However, it is also possible to account for gas-phase absorption in a more straightforward manner by coding the surface-absorption signal via the application of a polarization modulation (PM) technique to a conventional RAIR spectrometer. The efficiency of polarization modulation RAIRS in discriminating near-surface absorptions from the isotropic stray absorptions occurring in the gas phase has been demonstrated for both a setup using a dispersive infrared spectrometer and a setup using a Fourier transform (FT) spectrometer. , The adsorption of CO and NO on polycrystalline Pt foils has been investigated by PM-RAIRS under CO pressure of up to 50 mbar, , but in principle there is no limitation to applying higher pressures.…”

Section: Introductionmentioning

confidence: 99%

Polarization Modulation Infrared Reflection Absorption Spectroscopy of CO Adsorption on Co(0001) under a High-Pressure Regime

et al. 1996

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The adsorption of CO on Co(0001) has been investigated in situ by polarization modulation infrared reflection absorption spectroscopy (PM-RAIRS), which has been applied for the first time in a study of a model system for a heterogeneous catalyst. The CO/Co(0001) system was studied in the pressure range from 10 -10 to 600 mbar at temperatures between 300 and 550 K, showing the in situ potential of PM-RAIRS and the significant scope of this method for catalysis research. Linearly and bridge-bonded CO species could be distinguished on well-annealed surfaces. High-pressure RAIRS experiments done at room temperature were in agreement with previous low-energy electron diffraction (LEED) investigations in ultrahigh vacuum (UHV) at 100 K, 3,4 indicating a transition in the CO layer from a ( 3 × 3)R30°to a (2 3 × 2 3)R30°structure with increasing CO coverage. By comparison of well-annealed and Ar-sputtered (defective) surfaces, we could identify, at a high frequency of around 2080 cm -1 , a CO species attached to defect sites. It is shown that annealing at 450-490 K at 100 mbar of CO pressure leads to the creation of defects at the cobalt surface. The defects influence the structure of the CO overlayer. The nature of this "defect"-bound CO is discussed. Postreaction X-ray photoelectron spectroscopy (XPS) showed the development of surface carbide upon annealing in CO, which is in good agreement with the vanishing of the RAIRS signal of adsorbed CO at temperatures above 520 K.

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“…Because gas-phase absorption has no polarization dependence, PM-RAIRS is capable of measuring small surface absorptions even when obscured by a highly absorbing gas phase. 38 This has been particularly useful for examining catalytic surfaces under realistic, high-pressure conditions 39 but also for removing atmospheric CO 2 and H 2 O contributions under ambient conditions. 40 While commercially available photoelastic modulators (PEMs) are commonly used for PM-RAIRS, their modulation frequencies only permit switching between polarizations at a maximum frequency of 100 kHz.…”

Section: Methodsmentioning

confidence: 99%

Time-Resolved Surface Infrared Spectroscopy during Atomic Layer Deposition

et al. 2013

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This work presents a novel method for obtaining surface infrared spectra with sub-second time resolution during atomic layer deposition (ALD). Using a rapid-scan Fourier transform infrared (FT-IR) spectrometer, we obtain a series of synchronized interferograms (120 ms) during multiple ALD cycles to observe the dynamics of an average ALD cycle. We use a buried metal layer (BML) substrate to enhance absorption by the surface species. The surface selection rules of the BML allow us to determine the contribution from the substrate surface as opposed to that from gas-phase molecules and species adsorbed at the windows. In addition, we use simulation to examine the origins of increased reflectivity associated with phonon absorption by the oxide layers. The simulations are also used to determine the decay in enhancement by the buried metal layer substrate as the oxide layer grows during the experiment. These calculations are used to estimate the optimal number of ALD cycles for our experimental method.

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The infrared spectrum of adsorbed carbon monoxide on a platinum surface in the presence of high pressure gas-phase carbon monoxide

Cited by 49 publications

References 1 publication

In Situ Characterization of Adsorbates in Solid−Liquid Interfaces by Reflection−Absorption Infrared Spectroscopy

In Situ Characterization of Adsorbates in Solid−Liquid Interfaces by Reflection−Absorption Infrared Spectroscopy

Polarization Modulation Infrared Reflection Absorption Spectroscopy of CO Adsorption on Co(0001) under a High-Pressure Regime

Time-Resolved Surface Infrared Spectroscopy during Atomic Layer Deposition

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