CO monolayer oxidation at Pt nanoparticles supported on glassy carbon electrodes

Cherstiouk, Olga V.; Simonov, P.A.; Зайковский, В. И.; Savinova, Elena R.

doi:10.1016/s0022-0728(03)00198-0

Cited by 98 publications

(107 citation statements)

References 33 publications

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“…The ECA was estimated from CO stripping charge assuming a specific charge of 420 μC/cm 2 Pt . 43,44 Electrolyte solution resistance (R soln ) between the RE and WE (∼21−23 ohm in 0.1 M HClO 4 ) was measured via a built-in current interrupter or alternatively from the high frequency resistance (HFR) obtained from electrochemical impedance spectroscopy (EIS). Linear sweep voltammetry (LSV) was imposed after purging the cell with oxygen for 10 min to obtain the ORR activity with the iR soln drop corrected by the potentiostat during the LSV measurement.…”

Section: Methodsmentioning

confidence: 99%

Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique

Shinozaki

Zack

Richards

et al. 2015

J. Electrochem. Soc.

308

351

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The rotating disk electrode (RDE) technique is being extensively used as a screening tool to estimate the activity of novel PEMFC electrocatalysts synthesized in lab-scale (mg) quantities. Discrepancies in measured activity attributable to glassware and electrolyte impurity levels, as well as conditioning, protocols and corrections are prevalent in the literature. The electrochemical response to a broad spectrum of commercially sourced perchloric acid and the effect of acid molarity on impurity levels and solution resistance were also assessed. Our findings reveal that an area specific activity (SA) exceeding 2.0 mA/cm 2 (20 mV/s, 25 • C, 100 kPa, 0.1 M HClO 4 ) for polished poly-Pt is an indicator of impurity levels that do not impede the accurate measurement of the ORR activity of Pt based catalysts. After exploring various conditioning protocols to approach maximum utilization of the electrochemical area (ECA) and peak ORR activity without introducing catalyst degradation, an investigation of measurement protocols for ECA and ORR activity was conducted. Down-selected protocols were based on the criteria of reproducibility, duration of experiments, impurity effects and magnitude of pseudo-capacitive background correction. Statistical reproducibility of ORR activity for poly-Pt and Pt supported on high surface area carbon was demonstrated.

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Section: Methodsmentioning

confidence: 99%

Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique

Shinozaki

Zack

Richards

et al. 2015

J. Electrochem. Soc.

308

351

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“…That the positive shift on the Pt-Rh(111) particles is less pronounced than that reported in the literature may be due to the fact that the geometry of the particles generated by voltammetric deposition is different. The particles are flatter and larger in diameter than particles generated from colloidal solutions [48,49] or reduction of a droplet of platinum-containing solution [50][51][52] and, thus, can be expected to react differently. As the particles reach a size of about 10 nm in diameter, the properties of polycrystalline platinum start to dominate and, consequently, the CO oxidation peak shifts to lower potentials.…”

Section: Cyclic Voltammetry Saturated Co-adlayer Oxidationmentioning

confidence: 99%

“…Similar observations were also made by Maillard et al and Cherstiouk et al for CO-adlayer stripping on platinum nanoparticles supported on glassy carbon (generated by reduction of dried droplet of a H 2 PtCl 4 solution in H 2 gas). [50][51][52] They found that as the particle size is decreased below 3 nm, the overpotential for CO oxidation shifts to considerably higher potentials. Restricted mobility of CO ads on smaller particles was suggested to be responsible for this phenomenon.…”

Section: Cyclic Voltammetry Saturated Co-adlayer Oxidationmentioning

confidence: 99%

CO Oxidation on Pt‐Modified Rh(111) Electrodes

et al. 2005

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The CO electro-oxidation reaction was studied on platinum-modified Rh(111) electrodes in 0.5 M H2SO4 using cyclic voltammetry and chronoamperometry. The Pt-Rh(111) electrodes were generated during voltammetric cycles at 50 mV s(-1) in a 30 microM H2PtCl6 and 0.5 M H2SO4 solution. Surfaces generated by n deposition cycles were investigated (Ptn-Rh(111) with n=2, 4, 6, 8, 10, and 16). The blank cyclic voltammograms of these surfaces are characterized by a pronounced sharpening of the hydrogen/(bi)sulfate adsorption/desorption peaks, typical for Rh(111), and the appearance of contributions between 0.1 and 0.4 V, which were ascribed to hydrogen/(bi)sulfate adsorption/desorption on the deposited platinum. At higher potentials, the surface oxidation of Rh(111) is enhanced by the presence of platinum. The structure of the Pt-modified electrodes was investigated by STM imaging. At low Pt coverages (Pt2-Rh(111)), monoatomically high islands are formed, which grow three dimensionally as the number of deposition cycles increases. After eight cycles, the monolayer islands have grown in diameter and range from mono- to multiatomic height. At even higher Pt coverage (Pt16-Rh(111)), the islands grow to particles of approx. 10 nm in diameter, which are 5-6 atoms high. The CO stripping voltammetry on these surfaces is characterized by two peaks: A low-potential, structure-insensitive peak, ascribed to CO reacting at the platinum monolayer islands, whose onset is shifted 150, 250, and 100 mV negatively with respect to pure Rh(111), Pt(111), and polycrystalline Pt, respectively, indicating the enhanced CO electro-oxidation properties of the Pt overlayer system. A peak at higher potentials displays strong structure sensitivity (particle-size effect) and was ascribed to CO reacting on the islands of multiatomic height. Current-time transients recorded on the surface with the highest amount of monolayer islands (Pt4-Rh(111)) also indicate enhanced CO-oxidation kinetics. Comparison of the Pt4-Rh(111) current-time transients recorded at 0.635, 0.675, and 0.750 V versus RHE (reversible hydrogen electrode) with those of pure Rh(111) and Pt(111) shows greatly reduced reaction times. A Cottrellian decay at long times indicates surface-diffusion-limited CO oxidation on the bare Rh(111) surface, while the peak visible at short times is indicative of CO reacting at the monolayer platinum islands. The results presented here show that, as indicated by density functional theory (DFT) calculations, the CO-adlayer oxidation for this system is enhanced compared to both pure Rh and Pt.

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“…Nanoparticle agglomeration causes different effects on the studied reaction. A typical example of this is the CO electrooxidation reaction on platinum nanoparticles [15,40]. These studies have shown that peak multiplicity and lower onset for CO oxidation are related to the nanoparticle agglomeration.…”

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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CO monolayer oxidation at Pt nanoparticles supported on glassy carbon electrodes

Cited by 98 publications

References 33 publications

Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique

Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique

CO Oxidation on Pt‐Modified Rh(111) Electrodes

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

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