Kinetic models of surface explosions

Please cite this article as: J. Joo, T. Uchida, A. Cuesta, M.T.M. Koper, M. Osawa , The effect of pH on the electrocatalytic oxidation of formic acid/formate on platinum: A mechanistic study by surface-enhanced infrared spectroscopy coupled with cyclic voltammetry, Electrochimica Acta (2014), http://dx.doi.org/10. 1016/j.electacta.2014.02.040 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe electrocatalytic oxidation of formic acid (HCOOH) and formate (HCOO − ) to CO 2 on platinum has been studied over a wide range of pH (0-12) by surface-enhanced infrared absorption spectroscopy (SEIRAS) coupled with cyclic voltammetry. The peak current of HCOOH/HCOO − oxidation exhibits a volcano-shaped pH dependence peaked at a pH close to the pK a of HCOOH (3.75). The experimental result is reasonably explained by a simple kinetic model that HCOO − oxidation is the dominant reaction route over the whole pH range.HCOOH is oxidized after being converted to HCOO − via the acid-base equilibrium. The ascending part of the volcano plot at pH < 4 is ascribed mostly to the increase of the molar ratio of HCOO − , while the descending part at pH > 4 is ascribed to the suppression of HCOO − oxidation by adsorbed OH or oxidation of the electrode surface. In acidic media, HCOOH is

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“…6). Island formation of bridge-bonded adsorbed formate has been suggested in both UHV [54] and electrochemical environment [55].…”

Section: Kinetic Modeling Of Hcooh/hcoo − Oxidationmentioning

confidence: 99%

The effect of pH on the electrocatalytic oxidation of formic acid/formate on platinum: A mechanistic study by surface-enhanced infrared spectroscopy coupled with cyclic voltammetry

Joo

Uchida

Cuesta

et al. 2014

Electrochimica Acta

132

127

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“…This clustering should be observable in temperature programmed desorption where we would expect very sharp desorption peaks (surface explosions). 26 3.1.4 Vibrational spectra. There are three types of high frequency vibrational modes that occur on these terminations after adsorption of HF; two bending modes and a stretching mode, as depicted in Fig.…”

Section: Binding Energiesmentioning

confidence: 99%

Adsorption of HF and HCl on the β-AlF3 (100) surface

Bailey

Wander

Mukhopadhyay

et al. 2008

Phys. Chem. Chem. Phys.

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The current study employs hybrid-exchange density functional theory to investigate the adsorption of HF and HCl to under-coordinated Al ions on the beta-AlF(3) (100) surface. It is shown that the geometries of the adsorbates are strongly dependent on coverage. Furthermore, the adsorption of HCl leads to a number of distinct structures that have very similar energies. It is proposed that this result may explain the high catalytic activity of aluminium fluoride and aluminium chloro-fluoride surfaces towards chlorine-fluorine exchange reactions. The stretching and bending frequencies of the H-F and H-Cl bonds at half and full monolayer coverage are also calculated and the vibrational spectrum is found to be strongly dependent on the adsorption site and the coverage. The vibrational frequency shifts provide, therefore, a mechanism for experimentally characterising these surfaces.

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“…The rate of the decomposition is remarkably slowed down at high formate (or acetate) coverage ( θ f ), and once the reaction is initiated the rate is increased explosively , which is called surface explosion 16. The suppression of the reaction before the explosion has been explained by the adsorbed species themselves blocking each other's decomposition by steric hindrance 16b,c. The necessity for the suppression is high local coverage (practically independent of the global coverage) 16b,c.…”

mentioning

confidence: 98%

“…The suppression of the reaction before the explosion has been explained by the adsorbed species themselves blocking each other's decomposition by steric hindrance 16b,c. The necessity for the suppression is high local coverage (practically independent of the global coverage) 16b,c. This condition is likely to be fulfilled in the electrooxidation of formic acid, judging by the potential dependence of the CO L vibrational frequency (Figure 3 c).…”

mentioning

confidence: 99%

Current Oscillations during Formic Acid Oxidation on a Pt Electrode: Insight into the Mechanism by Time‐Resolved IR Spectroscopy

2005

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Revised model: Current oscillations in the electrooxidation of formic acid at a fixed potential can be observed by time‐resolved surface‐enhanced infrared absorption spectroscopy (see picture). Real‐time probing of the reaction dynamics on the electrode surface provides new insight into the oscillations that are not accessible by conventional techniques. The reaction mechanism involves adsorbed formate as a reactive intermediate.

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Kinetic models of surface explosions

Cited by 28 publications

References 31 publications

The effect of pH on the electrocatalytic oxidation of formic acid/formate on platinum: A mechanistic study by surface-enhanced infrared spectroscopy coupled with cyclic voltammetry

The effect of pH on the electrocatalytic oxidation of formic acid/formate on platinum: A mechanistic study by surface-enhanced infrared spectroscopy coupled with cyclic voltammetry

Adsorption of HF and HCl on the β-AlF3 (100) surface

Current Oscillations during Formic Acid Oxidation on a Pt Electrode: Insight into the Mechanism by Time‐Resolved IR Spectroscopy

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