Oxidation of isotopically-labeled ethanol on platinum–tin–rhodium surfaces: Enhancing the production of CO2 from methyl groups

Mello, Gisele A.B.; Farias, Manuel J. S.; Giz, M. Janete; Câmara, Giuseppe A.

doi:10.1016/j.elecom.2014.09.009

Cited by 8 publications

(5 citation statements)

References 22 publications

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“…In recent years, PtRh x Sn y and PtRh x (SnO 2 ) y were considered promising candidates for anode catalysts. It was reported in ex situ studies by several groups that these catalysts may show high activity towards ethanol oxidation and it was proposed that it may be a result of facilitated carbon dioxide formation, based on IR spectroscopy measurements [23][24][25][26][27][28][29][30][31][32]. However, in situ experiments showed that power densities obtained for fuel cells with such catalysts (max.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

2019

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Here, we report for the first time the results of systematic characterization of a low-temperature polymer electrolyte membrane direct ethanol fuel cell using DC and AC electrochemical methods. Model catalysts (carbon supported Pt nanoparticles) painted on carbon paper are used as anode and cathode. Influence of physical parameters, such as cell temperature, current density, and ethanol concentration, and anode fuel flow rate on overall cell impedance is studied. Analysis of the obtained impedance spectra in connection with DC measurements allows us to comment on cell properties and to separate different contributions to the overall cell polarization. Our results suggest that the cell impedance is dominated by anode faradaic impedance, with a small or negligible contribution from cathode faradaic impedance. The anode impedance depends strongly on current density and cell temperature, but is not significantly influenced by ethanol concentration. Presence of anode mass-transfer impedance, even when ethanol was fed to the cell in high excess, is confirmed. Based on the results, we conclude that changes in ethanol electrooxidation mechanism might manifest themselves on the impedance spectra in the low-frequency inductive loop. Nonetheless, further studies involving equivalent circuit modelling are needed to determine the exact influence of the cell parameters on the anode kinetics.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

2019

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“…Aimed at electrocatalytic applications, the electrodeposition of metals [M (aq) z + + S (s) + z e – → M / S (s) ] is a widely studied field for the fabrication of bimetallic and multimetallic materials resulting in different surface structures. − These structures usually exhibit catalytic activities superior to those of the individual metals. In many cases, in situ STM (scanning tunneling microscopy) studies showed that the growth of new structures (for instance, one-dimensional chains and two-dimensional ad-islands) on a base substrate is strongly influenced by the presence of sites with low coordination numbers (steps, defects, kinks, etc.…”

Section: Introductionmentioning

confidence: 99%

“…[34][35][36][37] These structures usually exhibit catalytic activities superior than the individual metals. In many cases, in situ STM (Scanning Tunneling Microscopy) studies shown that the growth of new structures (for instance, one-dimension chains and two-dimension ad-islands) on a base substrate is strongly influenced by the presence of sites with low coordination number (steps, defects, kinks and so on), on which metal deposition starts.…”

Section: Introductionmentioning

confidence: 99%

Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation

et al. 2016

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In heterogeneous (electro)catalysis, the overall catalytic output results from responses of surface sites with different catalytic activities, and their discrimination in terms of what specific site is responsible for a given activity is not an easy task. Here, we use the electrooxidation of CO as a probe reaction to access the catalytic activity of different sites on high Miller index stepped Pt surfaces with their {110} steps selectively modified by Ru at different coverage. Data from in situ FTIR spectroscopy and cyclic voltammetry evidence that Ru deposited on {110} steps modifies the surface in a non-trivial way, only favoring the electrocatalytic oxidation of CO over {111} terraces. Moreover, these {111} terraces become catalytically active throughout a large potential window. On the other hand, after the deposition of Ru on {110} steps, the partial oxidation of a CO adlayer (by stripping voltammetry and in situ FTIR potential steps) show that those {110} steps that remain free of Ru seem to be not influenced by the presence of this metal. As a result, the remaining CO adlayer is oxidized on these Ru-free {110} steps at potentials identical to those observed in steps of pure stepped Pt surfaces (in absence of Ru). Firstly, these This is a previous version of the article published in ACS Catalysis. 2016, 6(5): 2997-3007. doi:10.1021/acscatal.6b00439 2 findings suggest that COads behaves as a motionless species during its oxidation. Secondly, they evidence that the impact caused by the presence of Ru in the catalytic activity of Pt(s)-[(n-1)(111)×(110)] stepped surfaces depends on the crystallographic orientation of Pt sites. These results help us to shed new light about the role of Ru in the mechanism of oxidation of CO and allow a deeper understanding regarding the CO tolerance in Pt-Ru catalysts.

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“…The strategies to improve the electrocatalysis of this reaction seek electrode materials that increase the rate of the C-C bond cleavage and catalyze step (6) at lower potentials. Some alternatives for platinum are the use of (110) stepped surfaces on (111) terraces [24] or the presence of foreign atoms adsorbed on the Pt surface [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of ethanol on platinum nanoparticles: surface structure and aggregation effects in alkaline medium

Busó-Rogero

Solla-Gullón

Vidal‐Iglesias

et al. 2015

J Solid State Electrochem

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The ethanol oxidation reaction in 0.1 M NaOH on Pt nanoparticles with different shapes and loadings was investigated using electrochemical and spectroscopic techniques. The surface structure effect on this reaction was studied using well-characterized platinum nanoparticles. Regardless of the type of Pt nanoparticles used, results show that acetate is the main product with negligible CO2 formation. From the different samples used, the nanoparticles with a large amount (111) ordered domains have higher peak currents and a higher onset potential, in agreement with previous works with single crystal electrodes.In addition, spherical platinum nanoparticles supported on carbon with different loadings were used for studying possible diffusional problems of ethanol to the catalyst surface.The activity in these samples diminishes with the increase of Pt loading, due to diffusional problems of ethanol throughout the whole Pt nanoparticle layer, being the internal part of the catalyst layer inactive for the oxidation. To avoid this problem and prepare more dispersed nanoparticle catalyst layers, deposits were dried while the carbon support was rotated to favor the dispersion of the layer around the support. The improvement in the electrocatalytic activity for ethanol oxidation confirms the better performance of this procedure for depositing and drying.

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Oxidation of isotopically-labeled ethanol on platinum–tin–rhodium surfaces: Enhancing the production of CO2 from methyl groups

Cited by 8 publications

References 22 publications

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation

Oxidation of ethanol on platinum nanoparticles: surface structure and aggregation effects in alkaline medium

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