Reaction products of anodic oxidation of methanol in sulfuric acid solution

Ota, Kazutaka; Nakagawa, Yoshiro; Takahashi, Masao

doi:10.1016/s0022-0728(84)80286-7

Cited by 131 publications

(121 citation statements)

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“…This means that the existence of the ¦I (od) is not related to the oxidation of formic acid or formaldehyde, which is produced and dissolved into a solution during the oxidation of methanol. [14][15][16][17][18][19] Also it is not related to adsorption of sulfate or hydrogen sulfate because experiments on the oscillation during oxidation of formic acid or formaldehyde were also carried out with 0.5 M sulfuric acid. We presume the reason for the existence of the ¦I (od) is that methanol is most difficult to oxidize of the three C 1 compounds, as supported from voltammograms.…”

Section: Comparison With Oscillation Behavior During Formic Acidmentioning

confidence: 99%

“…As for the direct path for the oxidation of methanol, it has been found from solution analysis 14,15 and differential electrochemical mass spectroscopy (DEMS) [16][17][18] that formaldehyde and formic acid are involved. Abd-El-Latif et al 19 have recently argued that methyl formate, the amount of which has often been assumed to be an indirect measure of that of formic acid formed, is directly formed on the surface but not in the liquid phase by esterification.…”

Section: Introductionmentioning

confidence: 99%

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Separate Current Range for Appearance of Potential Oscillation during Methanol Oxidation on Platinum

et al. 2014

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We have found that the current range is divided into two parts for the appearance of potential oscillation during methanol oxidation on polycrystalline platinum at 315 K when the methanol concentration is between 10 and 0.03 mol dm −3 (M). The current range for oscillation disappearance, named ΔI (od), increases with a decrease in the methanol concentration. At currents below the ΔI (od), the oscillation waveform is always a large-amplitude and long-period (sometimes of the order of an hour) oscillation, named oscillation L. At currents immediately above the ΔI (od), a small-amplitude and short-period oscillation, named oscillation S, is observed for 0.03 to 0.1 M methanol and oscillation L is for 0.3 to 10 M methanol. For the latter methanol concentrations, oscillation S also becomes observed at higher currents. Such a ΔI (od) has not been found for potential oscillations during formic acid or formaldehyde oxidation and, thus, the existence of the ΔI (od) is distinctive to potential oscillations during methanol oxidation.

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Section: Comparison With Oscillation Behavior During Formic Acidmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Separate Current Range for Appearance of Potential Oscillation during Methanol Oxidation on Platinum

et al. 2014

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“…Unfortunately, formation of surface poisoning species and soluble intermediates lowers the overall efficiency of the fuel cell. Carbon monoxide has been identified as the primary poisoning species in many different studies [10,[14][15][16][17], while formic acid and formaldehyde are formed as intermediate products [18][19][20][21]. It is generally accepted that the oxidation of methanol proceeds through a dual pathway, namely, a direct pathway involving the formation of intermediate species such as formic acid and formaldehyde and an indirect pathway via Fig.…”

Section: Introductionmentioning

confidence: 99%

The electrooxidation of small organic molecules on platinum nanoparticles supported on gold: influence of platinum deposition procedure

Scheijen

Beltramo

Hoeppener

et al. 2007

J Solid State Electrochem

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The electrocatalytic properties of small platinum nanoparticles were investigated for the oxidation of CO, methanol, and formic acid using voltammetry, chronoamperometry, and surface-enhanced Raman spectroscopy. The particles were generated by galvanostatic deposition of platinum on a polished gold surface from an H 2 PtCl 6 containing electrolyte and ranged between 10 and 20 nm in diameter for low platinum surface concentrations, 10 and 120 nm for medium concentrations, and full Pt monolayers for high concentrations. CO stripping and bulk CO oxidation experiments on the particles up to 120 nm in diameter displayed pronounced structural effects. The CO oxidation current-time transients show a current decay for low platinum coverages and a current maximum for medium and high coverages. These results were also observed in the literature for particles of 2-to 5-nm size and agglomerates of these particles. The similarities between the literature and our results, despite large differences in particle size and morphology, suggest that particle structure and morphology are also very important catalytic parameters. Surface-enhanced Raman spectroscopy data obtained for the oxidation of CO on the Pt-modified Au electrodes corroborate this conclusion. A difference in the ratio between CO adsorbed in linear-and bridge-bonded positions on the Pt nanoparticles of different sizes demonstrates the influence of the surface morphology. The oxidation activity of methanol was found to decrease with the particle size, while the formic acid oxidation rate increases. Again, a structural effect is observed for particles of up to ca. 120 nm in diameter, which is much larger than the particles for which a particle size effect was reported in the literature. The particle shape effect for the methanol oxidation reaction can be explained by a reduction in available "ensemble sites" and a reduction in the mobility of CO formed by decomposition of methanol. As formic acid does not require Pt ensemble sites, decreasing the particle size, and thus, the relative number of defects, increases the reaction rate.

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“…Characteristic signals in mass spectrometry are also absent. An interesting contribution is presented by Ota, 15 using PtPt electrodes and standard analytical methods (Figure 11). Following the rate of CO 2 formation and the concentrations of HCHO and HCOOH in solution with time, these data of at least three different parallel pathways become constant only after about 20 h. After this time, obviously the rates of formation for the two soluble intermediates become equal to the rates of consumption at the electrode.…”

Section: Parallel Pathways Of Methanol Oxidationmentioning

confidence: 99%

Electrochemical energy conversion: methanol fuel cell as example

Vielstich¹

2003

J. Braz. Chem. Soc.

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Apresentamos aqui as limitações termodinâmicas e cinéticas da energia de conversão eletroquímica para o caso da cela de combustível metanol/oxigênio. A detecção de produtos e intermediários é demonstrada usando espectroscopia FTIR in situ e espectrometria de massas on line. A catálise bifuncional da oxidação do metanol pelas superfícies do tipo PtRu é explicada. Discutimos a formação de HCOOH e HCHO através de passos paralelos reacionais. Um exemplo da tecnologia do sistema DMFC é apresentado.Thermodynamic and kinetic limitations of the electrochemical energy conversion are presented for the case of a methanol/oxygen fuel cell. The detection of intermediates and products is demonstrated using insitu FTIR spectroscopy and online mass spectrometry. The bifunctional catalysis of methanol oxydation by PtRu model surfaces is explained. The formation of HCOOH and HCHO via parallel reaction pathways is discussed. An example of DMFC system technology is presented.

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Reaction products of anodic oxidation of methanol in sulfuric acid solution

Cited by 131 publications

References 3 publications

Separate Current Range for Appearance of Potential Oscillation during Methanol Oxidation on Platinum

Separate Current Range for Appearance of Potential Oscillation during Methanol Oxidation on Platinum

The electrooxidation of small organic molecules on platinum nanoparticles supported on gold: influence of platinum deposition procedure

Electrochemical energy conversion: methanol fuel cell as example

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